5v76
From Proteopedia
Structure of Haliangium ochraceum BMC-T HO-3341
Structural highlights
FunctionBMCT3_HALO1 A minor component of the bacterial microcompartment (BMC) shell. Expression of 5 proteins in E.coli (BMC-H (Hoch_5815), BMC-P (Hoch_5814), and 3 BMC-T (Hoch_5812, Hoch_5816, Hoch_3341)) forms 40 nm artificial BMCs with a molecular mass of 6.5 MDa. One of 2 stacked pseudohexamers in the BMC. There are 20 BMC-T pseudohexamers per BMC, composed of mixed BMC-T1, BMC-T2 and BMC-T3. The shell facets are 20-30 Angstroms thick, with 1 of the stacked BMC-T trimers protruding to the exterior (PubMed:28642439, PubMed:30833088). The stacked trimers may serve as conduits to allow metabolite flux across the protein shell, gated by Arg-68 which contacts Glu-67 in an adjacent subunit; they are flexible enough to play a role in accommodating variations in shell assembly (Probable).[1] [2] [3] Publication Abstract from PubMedMany bacteria contain primitive organelles composed entirely of protein. These bacterial microcompartments share a common architecture of an enzymatic core encapsulated in a selectively permeable protein shell; prominent examples include the carboxysome for CO2 fixation and catabolic microcompartments found in many pathogenic microbes. The shell sequesters enzymatic reactions from the cytosol, analogous to the lipid-based membrane of eukaryotic organelles. Despite available structural information for single building blocks, the principles of shell assembly have remained elusive. We present the crystal structure of an intact shell from Haliangium ochraceum, revealing the basic principles of bacterial microcompartment shell construction. Given the conservation among shell proteins of all bacterial microcompartments, these principles apply to functionally diverse organelles and can inform the design and engineering of shells with new functionalities. Assembly principles and structure of a 6.5-MDa bacterial microcompartment shell.,Sutter M, Greber B, Aussignargues C, Kerfeld CA Science. 2017 Jun 23;356(6344):1293-1297. doi: 10.1126/science.aan3289. PMID:28642439[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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