From structure to function: YrbI from Haemophilus influenzae (HI1679) is a phosphatase.

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TitleFrom structure to function: YrbI from Haemophilus influenzae (HI1679) is a phosphatase.
Publication TypeJournal Article
Year of Publication2002
AuthorsParsons, JF, Lim, K, Tempczyk, A, Krajewski, W, Eisenstein, E, Herzberg, O
JournalProteins
Volume46
Issue4
Pagination393-404
Date Published2002 Mar 1
ISSN1097-0134
KeywordsAmino Acid Sequence, Bacterial Proteins, Binding Sites, Catalysis, Crystallography, X-Ray, Escherichia coli Proteins, Haemophilus influenzae, Models, Chemical, Models, Molecular, Molecular Sequence Data, Operon, Phosphoric Monoester Hydrolases, Protein Folding, Protein Structure, Secondary, Protein Subunits, Sequence Homology, Amino Acid, Structure-Activity Relationship
Abstract

The crystal structure of the YrbI protein from Haemophilus influenzae (HI1679) was determined at a 1.67-A resolution. The function of the protein had not been assigned previously, and it is annotated as hypothetical in sequence databases. The protein exhibits the alpha/beta-hydrolase fold (also termed the Rossmann fold) and resembles most closely the fold of the L-2-haloacid dehalogenase (HAD) superfamily. Following this observation, a detailed sequence analysis revealed remote homology to two members of the HAD superfamily, the P-domain of Ca(2+) ATPase and phosphoserine phosphatase. The 19-kDa chains of HI1679 form a tetramer both in solution and in the crystalline form. The four monomers are arranged in a ring such that four beta-hairpin loops, each inserted after the first beta-strand of the core alpha/beta-fold, form an eight-stranded barrel at the center of the assembly. Four active sites are located at the subunit interfaces. Each active site is occupied by a cobalt ion, a metal used for crystallization. The cobalt is octahedrally coordinated to two aspartate side-chains, a backbone oxygen, and three solvent molecules, indicating that the physiological metal may be magnesium. HI1679 hydrolyzes a number of phosphates, including 6-phosphogluconate and phosphotyrosine, suggesting that it functions as a phosphatase in vivo. The physiological substrate is yet to be identified; however the location of the gene on the yrb operon suggests involvement in sugar metabolism.

Alternate JournalProteins
PubMed ID11835514
PubMed Central IDPMC3762886
Grant List1P41RR12408-01A1 / RR / NCRR NIH HHS / United States
P01 GM057890 / GM / NIGMS NIH HHS / United States
P01-GM57890 / GM / NIGMS NIH HHS / United States