Structural insights into RipC, a putative citrate lyase β subunit from a Yersinia pestis virulence operon.
Yersinia pestis remains a threat, with outbreaks of plague occurring in rural areas and its emergence as a weapon of bioterrorism; thus, an improved understanding of its various pathogenicity pathways is warranted. The rip (required for intracellular proliferation) virulence operon is required for Y. pestis survival in interferon-γ-treated macrophages and has been implicated in lowering macrophage-produced nitric oxide levels. RipC, one of three gene products from the rip operon, is annotated as a citrate lyase β subunit. Furthermore, the Y. pestis genome lacks genes that encode citrate lyase α and γ subunits, suggesting a unique functional role of RipC in the Y. pestis rip-mediated survival pathway. Here, the 2.45 Å resolution crystal structure of RipC revealed a homotrimer in which each monomer consists of a (β/α)(8) TIM-barrel fold. Furthermore, the trimeric state was confirmed in solution by size-exclusion chromatography. Through sequence and structure comparisons with homologous proteins, it is proposed that RipC is a putative CoA- or CoA-derivative binding protein.
Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA.
Rodrigo
R
Torres
Nicholas
N
Chim
Banumathi
B
Sankaran
Céline
C
Pujol
James B
JB
Bliska
Celia W
CW
Goulding
D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics; D009876:Operon; D007652:Oxo-Acid-Lyases / Q000737:chemistry* / Q000235:genetics; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics; D016415:Sequence Alignment; D014774:Virulence; D015010:Yersinia pestis / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity
D009097:Multienzyme Complexes; D021122:Protein Subunits; D007652:Oxo-Acid-Lyases; C019909:citrate (pro-3S)-lyase