NMR structure of conserved eukaryotic protein ZK652.3 from C. elegans: a ubiquitin-like fold.

Abstract

Structural proteomics aims to provide one or more representative 3D structures for every structural domain family in nature. As part of an international effort in structural proteomics, the Northeast Structural Genomics Consortium has targeted clusters of strongly conserved eukaryotic protein families for structural and functional analysis. On this basis, protein ZK652.3 (nesg WR41 / YOY3{_}CAEEL / Swiss-Prot P34661 / gi|17557033) from Caenorhabditis elegans was selected for structure determination. Expression of the ZK652.3 gene has been observed in a transcriptional profile of C. elegans genes, where it was one of a cluster of 89 genes whose expression levels co-varied during development1. The biochemical function of this protein is presently unknown. Sequencing of cDNA libraries shows that homologues of ZK652.3 occur widely in vertebrates and plants (Fig. 1). However, ZK652.3 homologues are conspicuously absent from the yeast and Drosophila genomes. Here we describe the three-dimensional structure of ZK652.3 determined by NMR spectroscopy and discuss structural similarities with other proteins which provide clues to potential biochemical functions.