Analysis of the structural consensus of the zinc coordination centers of metalloprotein structures

In a recent sequence-analysis study it was concluded that up to 10% of the human proteome could be comprised of zinc proteins, quite varied in the functional spread. The native structures of only few of the proteins are actually established. The elucidation of rest of the sequences of not just human but even other actively investigated genomes may benefit from knowledge of the structural consensus of the zinc-binding centers of the currently known zinc proteins. Nearly four hundred X-ray and NMR structures in the database of zinc-protein structures available as of April 2007 were investigated for geometry and conformation in the zinc-binding centers; separately for the structural and catalytic proteins and individually in the zinc centers coordinated to three and four amino-acid ligands. Enhanced cysteine involvement in agreement with the observation in human proteome has been detected in contrast with previous reports. Deviations from ideal coordination geometries are detected, possible underlying reasons are investigated, and correlations of geometry and conformation in zinc-coordination centers with protein function are established, providing possible benchmarks for putative zinc-binding patterns of the burgeoning genome data.