title: Members of the immunoglobulin superfamily in bacteria.
abstract: We report a prediction that two prokaryotic proteins contain immunoglobulin superfamily domains. Immunoglobulin-like folds have been identified previously in prokaryotic proteins, but these share no recognizable sequence similarity with eukaryotic immunoglobulin superfamily (IgSF) folds, and may be the result of the physics and chemistry of proteins favoring certain common folds. In contrast, the prokaryotic proteins identified have sequences whose match to the immunoglobulin superfamily can be detected by hidden Markov modeling, BLASTP matches, key residue analysis, and secondary structure predictions. We propose that these prokaryotic immunoglobulin-like domains are almost certain to be related by divergence from a common ancestor to eukaryotic immunoglobulin superfamily domains.
authors.affiliation: MRC Laboratory of Molecular Biology, Cambridge, England.
authors.forename: A
authors.initials: A
authors.lastname: Bateman
authors.forename: S R
authors.initials: SR
authors.lastname: Eddy
authors.forename: C
authors.initials: C
authors.lastname: Chothia
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002480:Cellulase / Q000737:chemistry; D064211:Connectin; D007070:Immunoglobulin A / Q000737:chemistry; D007136:Immunoglobulins / Q000737:chemistry*; D008390:Markov Chains; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry; D009219:Myosin-Light-Chain Kinase; D010446:Peptide Fragments; D010455:Peptides; D011494:Protein Kinases / Q000737:chemistry; D017433:Protein Structure, Secondary; D011961:Receptors, Fc / Q000737:chemistry; D017385:Sequence Homology
chemical_list: D001426:Bacterial Proteins; D064211:Connectin; D007070:Immunoglobulin A; D007136:Immunoglobulins; D009124:Muscle Proteins; D010446:Peptide Fragments; D010455:Peptides; D011961:Receptors, Fc; C060640:telokin; D011494:Protein Kinases; D009219:Myosin-Light-Chain Kinase; D002480:Cellulase