Interaction of Pneumococcal Histidine Triad Proteins with Human Complement

The histidine triad superfamily of nucleotide-binding proteins.

Histidine triad (HIT) proteins were until recently a superfamily of proteins that shared only sequence motifs. Crystal structures of nucleotide-bound forms of histidine triad nucleotide-binding protein (Hint) demonstrated that the conserved residues in HIT proteins are responsible for their distinctive, dimeric, 10-stranded half-barrel structures that form two identical purine nucleotide-bindin...

Interaction of pneumococcal antigens with complement in rats.

Complement activation with pneumococcal antigens was studied both in vitro and after injection of the antigens into rats. Whole pneumococci of various serotypes activated C3-C9 in rat serum treated with ethyleneglycol-bis (beta-aminoethyl ether)-N,N'-tetraacetic acid, although serotypes differed greatly in the extent of activation. Some purified pneumococcal capsular polysaccharides also activa...

FHIT (fragile histidine triad)

Fhit protein is a tumor suppressor with reduced or no expression in many types of cancer. Fhit expression is more frequently lost in cancers of individuals with familial mutations causing deficiency in DNA repair genes such as BRCA1 and BRCA2 and MSH2. In vitro Fhit acts as a hydrolase that cleaves diadenosine triphosphate (Ap3A) to ADP and AMP. The Fhit-Ap3A enzyme-substrate complex appears to...

Structural characterization of human histidine triad nucleotide-binding protein 2, a member of the histidine triad superfamily.

The histidine triad proteins (HITs) constitute a large and ubiquitous superfamily of nucleotide hydrolases. The human histidine triad nucleotide-binding proteins (hHints) are a distinct class of HITs noted for their acyl-AMP hydrolase and phosphoramidase activity. The first high-resolution crystal structures of hHint2 with and without bound AMP are described. The differences between hHint2 and ...

INTERACTION OF PROTEINS WITH SMALL MOLECULES