title: Structure-based analysis of catalysis and substrate definition in the HIT protein family.
abstract: The histidine triad (HIT) protein family is among the most ubiquitous and highly conserved in nature, but a biological activity has not yet been identified for any member of the HIT family. Fragile histidine triad protein (FHIT) and protein kinase C interacting protein (PKCI) were used in a structure-based approach to elucidate characteristics of in vivo ligands and reactions. Crystallographic structures of apo, substrate analog, pentacovalent transition-state analog, and product states of both enzymes reveal a catalytic mechanism and define substrate characteristics required for catalysis, thus unifying the HIT family as nucleotidyl hydrolases, transferases, or both. The approach described here may be useful in identifying structure-function relations between protein families identified through genomics.
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Lima
authors.forename: M G
authors.initials: MG
authors.lastname: Klein
authors.forename: W A
authors.initials: WA
authors.lastname: Hendrickson
mesh_terms: D017766:Acid Anhydride Hydrolases; D000241:Adenosine / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D019281:Dimerization; D015226:Dinucleoside Phosphates / Q000378:metabolism; D006860:Hydrogen Bonding; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D017973:Tungsten Compounds / Q000378:metabolism; D000099170:Bis(5'-adenosyl)triphosphatase
chemical_list: D017766:Acid Anhydride Hydrolases; D000241:Adenosine; D000244:Adenosine Diphosphate; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D015226:Dinucleoside Phosphates; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; D017973:Tungsten Compounds; D000099170:Bis(5'-adenosyl)triphosphatase; C523965:alpha,beta-methyleneadenosine 5'-diphosphate; C025399:sodium tungstate(VI)