As the mutations imply a change in the hydrophobicity of the amin

As the mutations imply a change in the hydrophobicity of the aminoacidic residue, Selleckchem AZD3965 a functional role cannot be excluded. The mutations were found in MSS cases that did not show any particular feature. We also found that the most common PIK3CA mutation (H1047R) was significantly associated with MSI phenotype. The association

is moderate and would benefit from confirmation on an indipendent series. An association between PIK3CA mutations and MSI has been reported or at least suggested in both colon and stomach cancer [8, 23, 24, 26]. At variance with our findings, in the two studies regarding gastric cancer and reporting mutations by MSI status, exon 9 and exon 20 mutations were evenly distributed between the subtypes [23, 24]. However, the small number of mutated MSI cases prevents statistical comparison. The fact that only one type of mutation was found in our series of MSI tumors

is not surprising as the narrow spectrum of alterations of MSI gastric tumors may, in turn, restrict the type of PIK3CA mutations that are oncogenic in that context. Despite the large series analyzed, we did not find any correlation of PIK3CA mutations with clinical pathological features of gastric cancers apart from the association between MSI and H1047R. The lack of associations suggests that alteration of PIK3CA is an event that occurs early in a subset of gastric cancers that progresses towards malignancy through other mechanisms. In fact, in a multivariate survival model there was no evident

effect of SC75741 supplier the presence of mutation on prognosis. Based on our meta-analysis, the ratio between mutation prevalences in exons 9 and 20 can be generally considered a signature of cancer type. In particular, we found a significant exon bias for colon cancer, breast cancer with ductal histotype and endometrium cancer. In colon cancer, exon 9 is significantly for more hit than exon 20. This confirms suggestions from previous studies [8, 23, 27]. The opposite mutational pattern was consistently found in studies regarding endometrial cancer with exon 20 largely more hit than exon 9. This peculiarity was already pointed out and suggests a specific mechanism of PI3KCA involvement for endometrial cancer [28–30]. It is less clear whether an exon bias exists in breast cancer as many studies are apparently contradictory (see Figure 1). However, for studies that did furnish the information about the histotype of each sample, we observed a different exon preference between lobular and ductal histotypes as already suggested [15]. For ductal histotype, exon 20 was significantly more hit compared to exon 9, whereas a slight but inverse tendency was found in series of lobular breast cancers. This pattern is not evident in studies where the information about histotype is not available, possibly as an result of mixing different kinds of tumours together.

Both of these studies exhibited significant positive association

Both of these studies exhibited significant positive association with SCCHN risk among non-Hispanic white subjects and the south Indian population, respectively [44, 62]. Correspondingly, in the current study, a statistically significant 1.5 or more-fold increase in SCCHN risk was associated with all the mutant genotypes of rs13181 (ERCC2), viz. homozygous mutant (CC) (OR 1.680, 95% CI 1.014 to 2.784, P = 0.0497), heterozygous (AC) (OR 1.531, 95% CI 1.092 to 2.149, P = 0.0167) and combined mutant (AC + CC) (OR 1.560, 95% CI 1.128 to 2.158, P = 0.0073) genotypes. Odds ratios adjusted

against gender or habits (smoking, tobacco chewing and pan masala) using logistic regression also corroborated with the findings made using crude odds ratios only in terms of association of these potential risk factors with significant SCCHN risk demonstrating this website a potential

role of these factors towards SCCHN susceptibility Conclusion The results of the present investigation indicate that the polymorphism rs13181 might be a risk factor for predisposition towards SCCHN and Breast cancer among north Indian subpopulations. The data generated from this study may have wide-ranging applications for further epidemiological and public health related research on the Indian population. learn more The degree of susceptibility to cancers is hypothesised to be the final product of a mishmash of high-risk ROS1 genetic polymorphic variants or SNPs in a subset of medium and low penetrance genes like DNA repair genes which, even in the absence of the highly penetrant variant cancer-associated alleles, may increase the degree of susceptibility towards cancers a few fold thus having a major impact on the population incidence of cancer [19]. Therefore, further initiatives towards the discovery of cancer susceptibility SNPs in other genes involved in the NER pathway and the unravelling of the functional aspects of interactions

between SNP alleles shall be highly beneficial to interpret these potentially meaningful differences that may be cancer-causing and should therefore be vital for revealing the probable synergistic effect of gene-gene and gene-environment interactions in cancer susceptibility. Acknowledgements AKM is a recipient of Senior Research Fellowship from Council of Scientific and Industrial Research, India. NS was a Women Scientist of Department of Science and Technology, Govt. of India. The work was also supported by CSIR network project NWP0034. This paper bears communication number 7677 of CDRI. References 1. Hoeijmakers JH: Genome maintenance mechanisms for preventing cancer. Nature 2001, 411: 366–374.CrossRefPubMed 2. Kastan MB, Onyekwere O, Sidransky D, Vogelstein B, Craig RW: Participation of p53 protein in the cellular response to DNA damage. Cancer Res 1991, 51: 6304–6311.PubMed 3.

This allows activation of pigA, carA and rap transcription Rap,

This allows activation of pigA, carA and rap transcription. Rap, which is activated via QS and the phosphate response, can then further activate carA and pigA transcription. This results in upregulation of both Car and Pig production via multiple pathways. Figure CX-5461 chemical structure 9 The proposed mechanism by P i limitation can upregulate secondary metabolism in Serratia 39006. In response to Pi limitation (or pstS mutation), PhoR activates PhoB by phosphorylation. Active PhoB can then activate transcription of smaI, pigA and rap (indicated using

solid arrows). Upregulation of smaI results in activation of the QS regulated genes (pigA, carA and rap), via AHL mediated SmaR derepression (indicated using dashed arrows). Rap then further activates carA and pigA expression (indicated using solid arrows). This results in upregulation of Pig and Car production. Multiple studies have linked Pi limitation to enhanced secondary metabolite production [17]. However,

the complex molecular mechanisms underlying phosphate-mediated regulation have proven difficult to elucidate. Extensive studies in Streptomyces species have shown that PhoPR (PhoBR) activates secondary metabolism in response to Pi limitation, including biosynthesis of undecylprodigiosin, a tripyrrole closely related to Pig [40, 41]. However, in Streptomyces, inactivation of PhoP or deletion of phoPR also activates secondary metabolism [41]. In contrast, deletion of phoB and/or phoR in Serratia 39006 had no impact on secondary metabolism, demonstrating clear differences between the regulatory selleck compound mechanisms employed by these distantly related bacteria. Although

the requirement for increased secondary metabolism under conditions of phosphate limitation is unclear, it has been proposed that enhanced secondary metabolism allows the production of compounds which may, for example, directly antagonise other microorganisms or act as signalling molecules, thereby providing producing organisms with a competitive advantage under nutrient deprived conditions [40, 42, 43]. Conclusion In conclusion, we have established that via the global transcriptional regulators PhoB, SmaR buy Neratinib and Rap, multiple inter-linked pathways are acting to upregulate secondary metabolism in Serratia 39006 under conditions of Pi limitation, highlighting the importance of Pig and Car production under these conditions. Methods Bacterial strains, plasmids, phage and culture conditions Bacterial strains and plasmids are listed in Additional File 1[44–49]. Serratia sp. ATCC 39006 derivative strains were grown at 30°C and E. coli strains were grown at 37°C in Luria broth (LB; 5 g l-1 yeast extract, 10 g l-1 bacto tryptone and 5 g l-1 NaCl), minimal media (0.1% w/v (NH4)2SO4, 0.41 mM MgSO4, 0.2% w/v glucose, 40 mM K2HPO4, 14.7 mM KH2PO4, pH 6.9–7.1) or in phosphate limiting (PL) media (0.1% w/v (NH4)2SO4, 0.41 mM MgSO4, 0.2% w/v glucose, 0.1 M HEPES, pH 6.9–7.

Succeeding bio-informatic studies identified a putative σ70-like

Succeeding bio-informatic studies identified a putative σ70-like -10 and -35 box (Figure 3a) (TATAAT respectively TTAAAA) and two imperfect putative NtcA binding sites (TGAN8CAC and GTAN12TAC). By running the complete intergenic region in BLAST at Cyanobase two conserved regions were also discovered. Both can be found in the intergenic regions of several genes in Nostoc PCC 7120 and URMC-099 cost Anabaena variabilis ATCC 29413 (data now shown). Their function is unclear but one of them shows similarity

to the consensus sequence WATCAANNNNTTR from the previously described IHF binding sites [26]. The second and third TSPs were identified inside the gene alr1422, 4 bp and 14 bp downstream of the putative translation start site. A new putative translation start site within the same frame was found 115 bp downstream from the previously suggested start site. By analysing the sequence of the

promoter region a -10 box (TATTTT and TATCAT), a -35 box (TTAAAC and TACCGA) and two putative NtcA binding sites (GTAN8AAC/GTN10AC) 147/157 bp and 62/72 bp upstream of the two TSPs were also identified. Figure 2 Northern blot analysis of hupW. Northern blot analysis of the relative amount of hupW transcripts of Nostoc PCC check details 7120 and Nostoc punctiforme under different growth conditions, using a probe against hupW in Nostoc punctiforme. The positions of rRNAs are indicated, as seen on gel. The equal loading of the RNA were analyzed by determine the relative amount of rnpB transcripts. Figure 3 Illustrations of the hupW operons. The hupW operon and surrounding genes in Nostoc PCC 7120 and Nostoc punctiforme. A. The transcription start point (TSP) and promoter region of hupW in Nostoc PCC 7120 together with the result from the reverse transcription Terminal deoxynucleotidyl transferase (RT) reaction and subsequent PCRs. The positions of primers used in the experiments are shown (Table 1). (+): PCR-fragment, (-): negative control without RT enzyme, gDNA: positive control with gDNA. B. Schematic presentation

showing TSP and promoter region of hupW together with RT-PCR detection of hupW transcripts in Nostoc punctiforme. The positions of primers used are shown (Table 1). (+): PCR-fragment, (-): negative control without RT, gDNA: positive control with gDNA. Results of PCR were visualized on a 1% agarose gel. For Nostoc punctiforme a transcript of hupW of about 1300 nt, is only present in N2-fixing cultures (Figure 2). 5′RACEs identified a single TSP 607 bp upstream of hupW in Nostoc punctiforme, together with a σ70-like -10 box sequence (TAGGCT) and a putative NtcA binding site (GTAN8CAC) located 40 bp upstream from the TSP (Figure 3b). The resulting transcript includes the upstream gene Npun_F0373, which was confirmed by RT-PCR using primers for the subsequent PCR covering the intergenic region and agrees with the result from the Northern blot experiments (Figure 2 and 3b).

In this retrospective study, the two subgroups (disease free or r

In this retrospective study, the two subgroups (disease free or relapsed) this website of patients were equally distributed for sex, age, grade and stage (Table 1). Table 1 Case series   Patients   Recurrent Non recurrent Sex        Male 33 32    Female 3 6 Age, years        <70 19 12    ≥70 17 26 Grade        Low 27 28    High 9 10 Stage        Ta 30 31    T1 6 7 All patients gave written informed consent for biological samples to be used for research purposes. The study protocol was reviewed and approved by the ‘Area Vasta’ Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) Ethics Committee. Macrodissection and DNA isolation Five 5-μm-thick sections were obtained from each

paraffin-embedded block. Macrodissection was GSK690693 solubility dmso performed on hematoxylin-eosin stained sections and only cancer tissue was used for DNA isolation. Genomic DNA was purified using QIAmp DNA FFPE Tissue (Qiagen, Milan), according to the manufacturer’s instructions. DNA was also isolated from a human bladder cancer cell line (HT1376) using Qiamp DNA minikit (Qiagen, Milan, Italy), according to the manufacturer’s

instructions. Methylation specific multiple ligation probe amplification (MS-MPLA) MS-MLPA was performed using at least 50 ng of genomic DNA dissolved in 1XTE buffer (Promega, Madison, WI, USA). DNA isolated from HT 1376 cell line was used as internal control for MS MLPA analysis (Figure 1). The methylation status of 24 tumor suppressor gene promoters was analyzed using the ME001C1 kit (MRC-Holland, Amsterdam, The Netherlands) (Table 2). Two different probes that recognize two different sites of the promoter region were used for genes RASSF1 and MLH. We excluded CDKN2B gene from the analysis because its probe is sensitive to improper Hha1 Etoposide price digestion in FFPE samples. In brief, DNA was denatured (10 min at 98°C) and cooled at 25°C, after which the probe mix was added to the samples and hybridization was performed by incubation at 60°C for 16–18 h. The reaction was divided equally in two vials, one for ligation and the other for ligation-digestion reaction for each tumor. We added a mix composed of Ligase-65 buffer, Ligase-65 enzyme

and water to the first vial and a mix of Ligase-65 Buffer, Ligase 65 enzyme, Hha1 enzyme (Promega, UK) and water to the second. The samples were then incubated at 49°C for 30 min. At the end of the ligation and ligation-digestion reactions, samples were amplified by adding a mix of PCR buffer, dNTPs and Taq polymerase. The PCR reaction was performed under the following conditions: 37 cycles at 95°C for 30 sec, 60°C for 30 sec and 72°C for 60 sec. The final incubation was performed at 73°C for 20 min. Figure 1 Electropherogram relating to a) undigested and b) digested HT1376 samples with methylation of APC and RASSF1 genes. Table 2 Summary of gene function and chromosomal localization Gene Function Chromosomal localization TIMP metallopeptidase inhibitor 3 (TIMP3) Invasion and metastasis 22q12.

ARMS detected an additional 32 mutations Eighteen of these were

ARMS detected an additional 32 mutations. Eighteen of these were not detected on the sequencing traces and 14 failed to sequence. Three mutations were detected by sequencing only. These were mutations that the ARMS assays were not designed to detect. (B) NSCLC mutations. Eight EGFR mutations were detected in the NSCLC samples by both methods. ARMS detected an additional 10 mutations. Two of these were not analysed

by sequencing as the DNA amount was too low and eight failed to sequence. Nine mutations were detected by sequencing only. These were mutations that the ARMS assays were not designed to detect. Note that there were 27 mutations in 26 patients as one sample was found to contain two mutations. DNA quantity and DMXAA molecular weight ability to detect mutations The first 121 of the melanoma samples yielding DNA were grouped by DNA yield to determine if at low DNA quantity MRT67307 ic50 the ability to detect mutations was reduced. The groupings (>5 copies, 5-9 copies, 10-49 copies, 50-99 copies, 100-500 copies and >500 copies) were based on the amount of DNA in the control reactions that could be used to estimate the amount of DNA in the sample. There were more groupings at the lower DNA concentration as it was thought that any effect would

be more likely to be observed in these samples. There was no decrease in the ability to detect mutations as the DNA amount decreased. Both DNA sequencing and ARMS gave similar results in each category although overall ARMS detected more mutations. As the DNA concentration increased the number of successful sequencing reactions also increased: at >50 copies per assay input, the analysis success rate was very similar for both ARMS and sequencing. The results are shown in Fig. 2. Figure 2 Mutation detection success on varying the amount of input DNA. The DNA yield was grouped into categories and the percentage of mutations detected calculated for each group. The n values are the successful number of sequencing and ARMS analyses. The

lower yielding samples did not show any decrease in the numbers of BRAF or NRAS mutations detected. Both DNA sequencing and ARMS gave similar results in each category although overall ARMS detected more mutations. As the DNA concentration increased the number of successful sequencing reactions also increased: at >50 copies per assay Carnitine palmitoyltransferase II input, the analysis success rate was very similar for both ARMS and sequencing. In some samples at high DNA concentrations (>1000 copies assay input) non-specific signal did occur in the ARMS. In these samples it was important to dilute DNA below 1000 copies per assay input and repeat the analysis. This only affected a minority of samples – most samples in excess of this DNA limit did not exhibit any non-specificity at all. Why this should occur in some samples and not others is not known but adds to the difficulty of analysing FF-PET DNA.

FACS analysis was performed with a FACSCalibur Flow cytometer (Be

FACS analysis was performed with a FACSCalibur Flow cytometer (Becton Dickinson, Heidelberg, Germany) using CellQuest Pro and WinMDI software. Unstimulated PBMC and

PBMC after incubation with allogeneic EpCAM+ HT-29 (ATCC Nr. CCL-244) or HER2/neu+ SK-BR-3 carcinoma cells (ATCC Nr. HTB-30) were used as negative controls. Clinical patient evaluation/toxicity and safety evaluation Careful patient monitoring was applied throughout the study. Clinical evaluation, including medical history and general physical exam, was performed at baseline and defined days during treatment (day of trAb infusion and the following day; day of restimulation P505-15 supplier and the following day). Patients were monitored for adverse events according to the National

Cancer Institute common toxicity criteria during each visit. Standard laboratory parameters and vital signs were tested before and after treatment Laboratory testing included complete blood count, electrolytes, creatinine, bilirubin, transaminases, and tumor marker (CA19-9 for gastric carcinoma, CA125 for ovarian carcinoma, CEA and CA125 for CUP). In addition, patients during trAb therapy were daily monitored for systemic cytokine responses. Blood samples were taken before, 24 hours and 48 h after every trAb application. Serum levels of IL-6, TNF-α, and sIL-2R were measured by ELISA (Biosource, Fleurs, Belgium). Immune reaction to mouse IgG was assessed by ELISA measurement of human anti-mouse antibody reaction (HAMA) before and 4 weeks after therapy. Response was evaluated by computed tomography two to three months

after trAb treatment and every two to three months until tumor progression. Statistical analysis Analysis of cytokine levels was performed using the Wilcoxon signed rank test. Correlation analysis was done by the chi-square contingency analysis. All tests were calculated by SAS statistical software using a Windows XP computer system. Results Patients’ characteristics Nine patients were treated between February click here 2005 and December 2007. Prior to study treatment, 6 patients underwent surgical resection with curative intent, 8 patients received chemotherapy. Four patients presented with synchronous PC, whereas five developed PC after surgery and chemotherapy. One patient was diagnosed with PC of carcinoma of unknown primary (CUP) during elective laparoscopic cholecystectomy. The patients’ demographic and primary treatment parameters are listed in Table 1. Table 1 Patients’ characteristics Pat. Age Sex Tumor entity TNM stage primary Surgical therapy primary tumor Chemotherapy before trAb Radiation before trAb EpCAM expression HER2/neu expression A 31 f Gastric pT4pN3M0 Gastrectomy + + + + B 64 f Ovarian pT3pN0M0 Adnexectomy, resect. of liver met.

It has been reported that SiO x N y films with high positive fixe

It has been reported that SiO x N y films with high positive fixed charge density (Q f) in the range of 1012 cm−2 is effective for field-effect passivation of n-type Si surfaces [2]. So far, several methods have been applied to grow SiO x N y films. For example, high-temperature (>900°C) processes such as the direct thermal oxynitridation of Si in NO or N2O ambient [4, 5] and the annealing of SiO2 in nitrogen-containing ambient [6, 7] have been widely used. However, the high-temperature processes suffer a large thermal budget and a redistribution problem of dopant atoms. Plasma-enhanced chemical vapor deposition (PECVD) process is a low-temperature alternative below 400°C [8–10]. However, the PECVD method needs toxic precursor gases,

and it is also noted that the interfacial properties prepared by this method are usually inferior to those of thermal oxides [11], because the deposition method does not consume the substrate Si Selleckchem Ion Channel Ligand Library unlike thermal oxidation. Moreover, in the films prepared by low-temperature Tipifarnib PECVD, the concentration of hydrogen atoms in the form of Si-OH and Si-H bonds is high, which are responsible for poor dielectric properties [12]. Nitridation of silicon oxide in low-pressure nitrogen plasma has also been investigated to fabricate SiO x N y at low temperatures [13, 14]. In the case of low-pressure nitrogen plasma, the ion bombardment of the film surface is a serious

problem to develop highly reliable ultra-large-scale integrated circuits [15]. Recently, we have studied the plasma oxidation of Si wafers to C-X-C chemokine receptor type 7 (CXCR-7) grow SiO2 films using atmospheric-pressure (AP) plasma generated by a 150-MHz very-high-frequency (VHF) electric field and demonstrated that high-quality SiO2 films can be obtained using He/O2 or Ar/O2 plasma at 400°C [16, 17]. We have also

reported that the AP VHF plasma oxidation process at 400°C is capable of producing material quality of SiO2 films comparable to those of high-temperature (>1,000°C) thermal oxides. The SiO2/Si structure with low interface state density (D it) around the midgap of 1.4 × 1010 cm−2 eV−1 and moderately high Q f of 5.3 × 1011 cm−2 has been demonstrated [18]. Therefore, addition of N into the SiO2 film by AP plasma oxidation-nitridation using O2 and N2 precursor gas mixture is an alternative approach for obtaining SiO x N y films at a low temperature of 400°C. The purpose of this work is to present a method for preparing SiO x N y films by AP VHF plasma oxidation-nitridation with a detailed analysis of interface properties of SiO x N y layer by capacitance-voltage (C-V) measurements on metal-SiO x N y -Si capacitors. Methods The details of the AP VHF plasma apparatus have been reported previously [18]. A schematic illustration of an electrode for AP VHF plasma oxidation-nitridation is shown in Figure 1. In the gap between the substrate and parallel-plate electrode, stable plasma is generated at atmospheric pressure with 150-MHz VHF power using a gas mixture of 1% O2/He.

Planta 226:1075–1086PubMedCrossRef Merchant SS, Allen MD, Kropat

Planta 226:1075–1086PubMedCrossRef Merchant SS, Allen MD, Kropat J, Moseley JL, Long JC, Tottey

S, Terauchi AM (2006) Between a rock and a hard place: trace element nutrition in Chlamydomonas. Biochim Biophys Acta 1763:578–594PubMedCrossRef Merchant GS-9973 ic50 SS, Prochnik SE, Vallon O, Harris EH, Karpowicz SJ, Witman GB et al (2007) The Chlamydomonas genome reveals the evolution of key animal and plant functions. Science 318:245–250PubMedCrossRef Minagawa J (2009) Light-harvesting proteins. In: Stern D, Witman GB, Harris EH (eds) The ‘Chlamydomonas sourcebook’, vol 2. Elsevier, Amsterdam, pp 503–540 Misumi O, Matsuzaki M, Nozaki H, Miyagishima SY, Mori T, Nishida K et al (2005) Cyanidioschyzon merolae genome. A tool for facilitating comparable studies on organelle biogenesis in photosynthetic eukaryotes. Plant Physiol 137:567–585PubMedCrossRef Moll B, Levine RP (1970) Characterization of a photosynthetic mutant strain of Chlamydomonas reinhardi deficient in phosphoribulokinase activity. Plant Physiol 46:576–580PubMedCrossRef Molnar A, Bassett A, Thuenemann E, Schwach F, Karkare

S, Ossowski S et al (2009) Highly specific gene silencing by artificial microRNAs in the unicellular alga Chlamydomonas reinhardtii. Plant J (Epub ahead of print) Moseley J, Grossman AR (2009) Phosphorus limitation from the physiological to the genomic. In: Harris EH, Stern D, Witman GB (eds) ‘The Chlamydomonas sourcebook’, pp 189–216 Moseley J, González-Ballester D, Pootakham W, Bailey S, Grossman AR (2009) Genetic interactions between regulators of Chlamydomonas phosphorus and sulfur deprivation responses. Genetics 181:889–905PubMedCrossRef Mulkidjanian AY, Koonin EV, Makarova KS, Mekhedov SL, Sorokin A, Wolf YI et al (2006) The cyanobacterial genome core and the origin of photosynthesis. Proc Natl Acad Sci USA 103:13126–13131PubMedCrossRef Nakao M, Okamoto S, Kohara M, Fujishiro T, Fujisawa T, Sato S, Tabata S, Kaneko T, Nakamura Y (2010) CyanoBase: the cyanobacteria genome database update 2010. Nucleic cAMP Acids Res 38:D379–D381PubMedCrossRef Naumann B,

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In the CsoS1D trimers, conformational changes in the absolutely c

In the CsoS1D trimers, conformational changes in the absolutely conserved pore loop residues Glu120 and Arg121 (Fig. 9) result in either a relatively large open pore of ~14 Å diameter or an occluded pore (Fig. 10). The large size of the CsoS1D pore, which would allow for free passage of RuBP, likely requires gating

to prevent the loss of important metabolites or infiltration of inhibitory species. Fig. 10 Electrostatic comparison of the two trimers of the tandem BMC-domain protein CsoS1D (PDB:3F56) and modeled representation of the “air-lock” mechanism for metabolite movement through the protein. Convex (top), concave (middle), and pore cross-section (bottom) views are shown for each of the two structures on the left. The top and bottom BMN 673 nmr images of the “air-lock” mechanism are generated from the same solved stacked structure from two different orientations. The middle

image is a hypothetical model generated in PyMOL by structurally aligning a copy of a closed trimer over the open trimer in the stacked structure. Red denotes negative charge and blue denotes positive charge Interestingly, in two independent crystal structures, the CsoS1D trimers stacked to form a dimer of trimers (Fig. 10). The two trimers were rotated ~60° with respect to each LCZ696 nmr other so that the C-terminal domain of a subunit in the upper trimer interacted with the N-terminal domain of a subunit in the lower trimer. The dimerization was across the concave face of each trimer, resulting in a large cavity of 13,613 Å3. Additional biophysical analyses that support the potential biological relevance for the dimer of trimers include a buried surface area of 6,573 Å2 and a shape correlation value of 0.70 (range of 0–1, 1 being a perfect fit and 0 being no interaction) between the two trimers

(Klein et al. 2009). The cavity could, like the pore gating, influence the flux of larger metabolites (e.g., RuBP, 3PGA) into and out of the carboxysome in a manner analogous to an airlock. For example, the trimer facing the cytosol would open to accept a metabolite and then close; subsequently, the trimer facing the carboxysome interior would open to allow for release of the metabolite from the cavity (Fig. 10). An ortholog to CsoS1D, with the locus tag slr0169 in Synechocystis sp. PCC6803, has also been identified in all β-carboxysome-containing cyanobacteria (Klein et al. 2009). It is ~200 amino acids in length and lacks ~50 N-terminal residues that are present in the α-cyanobacterial CsoS1D homologs. slr0169 contains the conserved Glu and Arg residues (Glu69, Arg70) responsible for gating the CsoS1D pore as well as the universally conserved edge Lys residues in the N- and C-terminal domains (Lys108, Lys212) for interacting with other hexamers to incorporate into the shell (Cai et al. in press). A second ~200 amino acid BMC-domain protein is found only in low-light adapted strains of Prochlorococcus and some marine Synechococcus species.