5lsr

Carboxysome shell protein CcmP from Synechococcus elongatus PCC 7942

spinqualitylabelsall models 5lsr, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5lsr is a 3 chain structure with sequence from Synechococcus elongatus PCC 7942 = FACHB-805. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.65Å Ligands: SCN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CCMP_SYNE7 Probably part of the carboxysome shell, a polyhedral inclusion where RuBisCO (ribulose bisphosphate carboxylase, rbcL-rbcS) is sequestered. It is thought that this protein controls transport of RuBisCO reactants in and out of the carboxysome; residual densities in the 4 X-ray structures suggest that differing compounds bind in interior pockets, depending on the open or closed state of the pore. Publication Abstract from PubMed Cyanobacterial CO2 fixation is promoted by encapsulating and co-localizing the CO2-fixing enzymes within a protein shell, the carboxysome. A key feature of the carboxysome is its ability to control selectively the flux of metabolites in and out of the shell. The beta-carboxysome shell protein CcmP has been shown to form a double layer of pseudohexamers with a relatively large central pore (~13 A diameter), which may allow passage of larger metabolites such as the substrate for CO2 fixation, ribulose 1,5-bisphosphate, through the shell. Here we describe two crystal structures, at 1.45 A and 1.65 A resolution, of CcmP from Synechococcus elongatus PCC7942 (SeCcmP). The central pore of CcmP is open or closed at its ends, depending on the conformation of two conserved residues, Glu69 and Arg70. The presence of glycerol resulted in a pore that is open at one end and closed at the opposite end. When glycerol was omitted, both ends of the barrel became closed. A binding pocket at the interior of the barrel featured residual density with distinct differences in size and shape depending on the conformation, open or closed, of the central pore of SeCcmP, suggestive of a metabolite-driven mechanism for the gating of the pore. Crystal structures of beta-carboxysome shell protein CcmP: ligand binding correlates with the closed or open central pore.,Larsson AM, Hasse D, Valegard K, Andersson I J Exp Bot. 2017 Mar 28. doi: 10.1093/jxb/erx070. PMID:28369612 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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