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Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues
Published on: July 14, 2015
Crystal structures of HINT demonstrate that histidine triad proteins are GalT-related nucleotide-binding proteins
C Brenner1, P Garrison, J Gilmour
1Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254, USA. brenner@dada.jci.tju.edu
Abstract:
Histidine triad nucleotide-binding protein (HINT), a dimeric purine nucleotide-binding protein from rabbit heart, is a member of the HIT (histidine triad) superfamily which includes HINT homologues and FHIT (HIT protein encoded at the chromosome 3 fragile site) homologues. Crystal structures of HINT-nucleotide complexes demonstrate that the most conserved residues in the superfamily mediate nucleotide binding and that the HIT motif forms part of the phosphate binding loop. Galactose-1-phosphate uridylyltransferase, whose deficiency causes galactosemia, contains tandem HINT domains with the same fold and mode of nucleotide binding as HINT despite having no overall sequence similarity. Features of FHIT, a diadenosine polyphosphate hydrolase and candidate tumour suppressor, are predicted from HINT-nucleotide structures.
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