title: Two Pfam protein families characterized by a crystal structure of protein lpg2210 from Legionella pneumophila.
abstract: BACKGROUND
  Every genome contains a large number of uncharacterized proteins that may encode entirely novel biological systems. Many of these uncharacterized proteins fall into related sequence families. By applying sequence and structural analysis we hope to provide insight into novel biology.
  
  
  RESULTS
  We analyze a previously uncharacterized Pfam protein family called DUF4424 [Pfam:PF14415]. The recently solved three-dimensional structure of the protein lpg2210 from Legionella pneumophila provides the first structural information pertaining to this family. This protein additionally includes the first representative structure of another Pfam family called the YARHG domain [Pfam:PF13308]. The Pfam family DUF4424 adopts a 19-stranded beta-sandwich fold that shows similarity to the N-terminal domain of leukotriene A-4 hydrolase. The YARHG domain forms an all-helical domain at the C-terminus. Structure analysis allows us to recognize distant similarities between the DUF4424 domain and individual domains of M1 aminopeptidases and tricorn proteases, which form massive proteasome-like capsids in both archaea and bacteria.
  
  
  CONCLUSIONS
  Based on our analyses we hypothesize that the DUF4424 domain may have a role in forming large, multi-component enzyme complexes. We suggest that the YARGH domain may play a role in binding a moiety in proximity with peptidoglycan, such as a hydrophobic outer membrane lipid or lipopolysaccharide.
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK. pcc@sanger.ac.uk.
authors.forename: Penelope
authors.initials: P
authors.lastname: Coggill
authors.forename: Ruth Y
authors.initials: RY
authors.lastname: Eberhardt
authors.forename: Robert D
authors.initials: RD
authors.lastname: Finn
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Chang
authors.forename: Lukasz
authors.initials: L
authors.lastname: Jaroszewski
authors.forename: Adam
authors.initials: A
authors.lastname: Godzik
authors.forename: Debanu
authors.initials: D
authors.lastname: Das
authors.forename: Qingping
authors.initials: Q
authors.lastname: Xu
authors.forename: Herbert L
authors.initials: HL
authors.lastname: Axelrod
authors.forename: L
authors.initials: L
authors.lastname: Aravind
authors.forename: Alexey G
authors.initials: AG
authors.lastname: Murzin
authors.forename: Alex
authors.initials: A
authors.lastname: Bateman
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D030562:Databases, Protein; D016952:Legionella pneumophila / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein
chemical_list: D001426:Bacterial Proteins