PMID: 16522806

Authors:

Manjasetty BA, Bussow K, Fieber-Erdmann M, Roske Y, Gobom J, Scheich C, Gotz F, Niesen FH, Heinemann U

Title:

Crystal structure of Homo sapiens PTD012 reveals a zinc-containing hydrolase fold.

Journal:

Protein Sci. 2006 Apr;15(4):914-20. Epub 2006 Mar 7.

Abstract:

The human protein PTD012 is the longer product of an alternatively spliced gene and was described to be localized in the nucleus. The X-ray structure analysis at 1.7 A resolution of PTD012 through SAD phasing reveals a monomeric protein and a novel fold. The shorter splice form was also studied and appears to be unfolded and non-functional. The structure of PTD012 displays an alphabetabetaalpha four-layer topology. A metal ion residing between the central beta-sheets is partially coordinated by three histidine residues. X-ray absorption near-edge structure (XANES) analysis identifies the PTD012-bound ion as Zn(2+). Tetrahedral coordination of the ion is completed by the carboxylate oxygen atom of an acetate molecule taken up from the crystallization buffer. The binding of Zn(2+) to PTD012 is reminiscent of zinc-containing enzymes such as carboxypeptidase, carbonic anhydrase, and beta-lactamase. Biochemical assays failed to demonstrate any of these enzyme activities in PTD012. However, PTD012 exhibits ester hydrolase activity on the substrate p-nitrophenyl acetate.