title: Bacterial pleckstrin homology domains: a prokaryotic origin for the PH domain.
abstract: Pleckstrin homology (PH) domains have been identified only in eukaryotic proteins to date. We have determined crystal structures for three members of an uncharacterized protein family (Pfam PF08000), which provide compelling evidence for the existence of PH-like domains in bacteria (PHb). The first two structures contain a single PHb domain that forms a dome-shaped, oligomeric ring with C(5) symmetry. The third structure has an additional helical hairpin attached at the C-terminus and forms a similar but much larger ring with C(12) symmetry. Thus, both molecular assemblies exhibit rare, higher-order, cyclic symmetry but preserve a similar arrangement of their PHb domains, which gives rise to a conserved hydrophilic surface at the intersection of the beta-strands of adjacent protomers that likely mediates protein-protein interactions. As a result of these structures, additional families of PHb domains were identified, suggesting that PH domains are much more widespread than originally anticipated. Thus, rather than being a eukaryotic innovation, the PH domain superfamily appears to have existed before prokaryotes and eukaryotes diverged.
authors.affiliation: Joint Center for Structural Genomics, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Qingping
authors.initials: Q
authors.lastname: Xu
authors.forename: Alex
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authors.forename: Debanu
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authors.forename: Kyle
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authors.forename: Dustin
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authors.forename: Carol L
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authors.lastname: Feuerhelm
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authors.lastname: Jaroszewski
authors.forename: Kevin K
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authors.lastname: Jin
authors.forename: Heath E
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authors.forename: Mark W
authors.initials: MW
authors.lastname: Knuth
authors.forename: Piotr
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authors.lastname: Kozbial
authors.forename: S Sri
authors.initials: SS
authors.lastname: Krishna
authors.forename: Abhinav
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authors.lastname: Kumar
authors.forename: David
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authors.lastname: Marciano
authors.forename: Daniel
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authors.lastname: McMullan
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authors.lastname: Miller
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Morse
authors.forename: Edward
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authors.lastname: Nigoghossian
authors.forename: Amanda
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authors.lastname: Nopakun
authors.forename: Linda
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authors.lastname: Okach
authors.forename: Christina
authors.initials: C
authors.lastname: Puckett
authors.forename: Ron
authors.initials: R
authors.lastname: Reyes
authors.forename: Christopher L
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authors.lastname: Rife
authors.forename: Natasha
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authors.lastname: Sefcovic
authors.forename: Henry J
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authors.lastname: Tien
authors.forename: Christine B
authors.initials: CB
authors.lastname: Trame
authors.forename: Henry
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authors.lastname: van den Bedem
authors.forename: Dana
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authors.lastname: Weekes
authors.forename: Tiffany
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authors.lastname: Wooten
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: John
authors.initials: J
authors.lastname: Wooley
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Elsliger
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Deacon
authors.forename: Adam
authors.initials: A
authors.lastname: Godzik
authors.forename: Scott A
authors.initials: SA
authors.lastname: Lesley
authors.forename: Ian A
authors.initials: IA
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mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D005057:Eukaryotic Cells; D019143:Evolution, Molecular; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000378:metabolism*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins