Crystal structures of YBHB and YBCL from Escherichia coli, two bacterial homologues to a Raf kinase inhibitor protein.
In rat and human cells, RKIP (previously known as PEBP) was characterized as an inhibitor of the MEK phosphorylation by Raf-1. In Escherichia coli, the genes ybhb and ybcl possibly encode two RKIP homologues while in the genomes of other bacteria and archaebacteria other homologous genes of RKIP have been found. The parallel between the cellular signaling mechanisms in eukaryotes and prokaryotes suggests that these bacterial proteins could be involved in the regulation of protein phosphorylation by kinases as well. We first showed that the proteins YBHB and YBCL were present in the cytoplasm and periplasm of E. coli, respectively, after which we determined their crystallographic structures. These structures verify that YBHB and YBCL belong to the same structural family as mammalian RKIP/PEBP proteins. The general fold and the anion binding site of these proteins are extremely well conserved between mammals and bacteria and suggest functional similarities. However, the bacterial proteins also exhibit some specific structural features, like a substrate binding pocket formed by the dimerization interface and the absence of cis peptide bonds. This structural variety should correspond to the recognition of multiple cellular partners.
Serre
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L
Centre de Biophysique Moléculaire, C.N.R.S., U.P.R. 4301, rue Charles Sadron 45071, Orléans, Cedex 2, France. laurence@cnrs-orleans.fr
Pereira de Jesus
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K
Zelwer
C
C
Bureaud
N
N
Schoentgen
F
F
Bénédetti
H
H
D000595:Amino Acid Sequence; D000727:Androgen-Binding Protein; D000838:Anions / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D019295:Computational Biology; D017124:Conserved Sequence / Q000235:genetics; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000737:chemistry; D019281:Dimerization; D004926:Escherichia coli / Q000737:chemistry* / Q000166:cytology / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial / Q000235:genetics; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D019897:Periplasm / Q000737:chemistry; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins; D060789:Prostatein; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D060765:Secretoglobins; D016415:Sequence Alignment; D017385:Sequence Homology; D013379:Substrate Specificity; D014598:Uteroglobin; D060788:Mammaglobin B
D000727:Androgen-Binding Protein; D000838:Anions; D019843:Archaeal Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; D049488:Phosphatidylethanolamine Binding Protein; D049294:Phospholipid Transfer Proteins; D060789:Prostatein; D060765:Secretoglobins; D014598:Uteroglobin; C511482:PEBP1 protein, human; C511484:Scgb1d2 protein, rat; C511483:Scgb1d4 protein, rat; C432085:ybcL protein, E coli; C432086:ybhB protein, E coli; C556468:Scgb2a1 protein, rat; D060788:Mammaglobin B