The structure of the pentameric shell protein MSM0273 from the RMM microcompartment

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.154 
  • R-Value Observed: 0.155 

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A Complete Structural Inventory of the Mycobacterial Microcompartment Shell Proteins Constrains Models of Global Architecture and Transport.

Mallette, E.Kimber, M.S.

(2017) J Biol Chem 292: 1197-1210

  • DOI: https://doi.org/10.1074/jbc.M116.754093
  • Primary Citation of Related Structures:  
    5L37, 5L38, 5L39, 5SUH

  • PubMed Abstract: 

    Bacterial microcompartments are bacterial analogs of eukaryotic organelles in that they spatially segregate aspects of cellular metabolism, but they do so by building not a lipid membrane but a thin polyhedral protein shell. Although multiple shell protein structures are known for several microcompartment types, additional uncharacterized components complicate systematic investigations of shell architecture. We report here the structures of all four proteins proposed to form the shell of an uncharacterized microcompartment designated the Rhodococcus and Mycobacterium microcompartment (RMM), which, along with crystal interactions and docking studies, suggests possible models for the particle's vertex and edge organization. MSM0272 is a typical hexameric β-sandwich shell protein thought to form the bulk of the facet. MSM0273 is a pentameric β-barrel shell protein that likely plugs the vertex of the particle. MSM0271 is an unusual double-ringed bacterial microcompartment shell protein whose rings are organized in an offset position relative to all known related proteins. MSM0275 is related to MSM0271 but self-organizes as linear strips that may line the facet edge; here, the presence of a novel extendable loop may help ameliorate poor packing geometry of the rigid main particle at the angled edges. In contrast to previously characterized homologs, both of these proteins show closed pores at both ends. This suggests a model where key interactions at the vertex and edges are mediated at the inner layer of the shell by MSM0271 (encircling MSM0273) and MSM0275, and the facet is built from MSM0272 hexamers tiling in the outer layer of the shell.

  • Organizational Affiliation

    From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
95Mycolicibacterium smegmatis MC2 155Mutation(s): 0 
Gene Names: MSMEG_0273MSMEI_0266
Find proteins for A0QP50 (Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155))
Explore A0QP50 
Go to UniProtKB:  A0QP50
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0QP50
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.154 
  • R-Value Observed: 0.155 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 69.97α = 90
b = 69.97β = 90
c = 140.09γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Natural Sciences and Engineering Research Council (NSERC, Canada)Canada04045-2015

Revision History  (Full details and data files)

  • Version 1.0: 2016-12-14
    Type: Initial release
  • Version 1.1: 2017-02-01
    Changes: Database references
  • Version 1.2: 2017-02-08
    Changes: Database references
  • Version 1.3: 2017-09-27
    Changes: Author supporting evidence
  • Version 1.4: 2020-01-08
    Changes: Author supporting evidence
  • Version 1.5: 2023-10-04
    Changes: Data collection, Database references, Refinement description