W0010

A New RNA-binding Motif Found in the Structure of Heat Shock Protein - 15kd. Staker, B.L., Korber, P., Bardwell, J.C.A., and Saper, M.A., 3250 Chemistry, BRD-1055, Univ. of Michigan, 930 N. University, Ann Arbor, MI 48108

The 2.0 Å structure of heat shock protein 15kd (Hsp15) reveals a novel RNA-binding motif. Hsp15 is an abundant protein which is highly inducible during heat shock.

Hsp15 is RNA binding and involved in ribosome repair. Comparison of its structure with those of two RNA-binding proteins, ribosomal protein S4 and threonyl-tRNA synthetase, reveals a novel RNA-binding motif. This newly recognized motif is remarkably common and present in at least eight different protein families that bind RNA. The surface of this motif in Hsp15 is populated by conserved, charged residues that define a likely RNA-binding site. An intriguing pattern emerges: stress proteins, ribosomal proteins and tRNA synthetases repeatedly share a conserved motif. This may imply a hitherto unrecognized functional similarity between these three protein classes.