Muramidase domain of SpmX from Asticaccaulis excentricus

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.216 

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This is version 1.3 of the entry. See complete history


Origin of a Core Bacterial Gene via Co-option and Detoxification of a Phage Lysin.

Randich, A.M.Kysela, D.T.Morlot, C.Brun, Y.V.

(2019) Curr Biol 29: 1634-1646.e6

  • DOI: https://doi.org/10.1016/j.cub.2019.04.032
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Temperate phages constitute a potentially beneficial genetic reservoir for bacterial innovation despite being selfish entities encoding an infection cycle inherently at odds with bacterial fitness. These phages integrate their genomes into the bacterial host during infection, donating new but deleterious genetic material: the phage genome encodes toxic genes, such as lysins, that kill the bacterium during the phage infection cycle. Remarkably, some bacteria have exploited the destructive properties of phage genes for their own benefit by co-opting them as toxins for functions related to bacterial warfare, virulence, and secretion. However, do toxic phage genes ever become raw material for functional innovation? Here, we report on a toxic phage gene whose product has lost its toxicity and has become a domain of a core cellular factor, SpmX, throughout the bacterial order Caulobacterales. Using a combination of phylogenetics, bioinformatics, structural biology, cell biology, and biochemistry, we have investigated the origin and function of SpmX and determined that its occurrence is the result of the detoxification of a phage peptidoglycan hydrolase gene. We show that the retained, attenuated activity of the phage-derived domain plays an important role in proper cell morphology and developmental regulation in representatives of this large bacterial clade. To our knowledge, this is the first observation of a phage gene domestication event in which a toxic phage gene has been co-opted for core cellular function at the root of a large bacterial clade.

  • Organizational Affiliation

    Department of Biology, Indiana University, 1001 E. 3rd Street, Bloomington, IN 47405, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
149Asticcacaulis excentricusMutation(s): 0 
Gene Names: Astex_1112
Find proteins for E8RMG8 (Asticcacaulis excentricus (strain ATCC 15261 / DSM 4724 / KCTC 12464 / NCIMB 9791 / VKM B-1370 / CB 48))
Explore E8RMG8 
Go to UniProtKB:  E8RMG8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE8RMG8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.256 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.216 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 100.44α = 90
b = 100.44β = 90
c = 96.62γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United States2R01GM051986

Revision History  (Full details and data files)

  • Version 1.0: 2019-05-22
    Type: Initial release
  • Version 1.1: 2019-05-29
    Changes: Data collection, Database references
  • Version 1.2: 2022-03-30
    Changes: Author supporting evidence, Database references
  • Version 1.3: 2024-01-17
    Changes: Data collection, Refinement description