1m5q

From Proteopedia

Crystal structure of a novel Sm-like archaeal protein from Pyrobaculum aerophilum

Overview

To better understand the roles of Sm proteins in forming the cores of many, RNA-processing ribonucleoproteins, we determined the crystal structure of, an atypical Sm-like archaeal protein (SmAP3) in which the conserved Sm, domain is augmented by a previously uncharacterized, mixed alpha/beta, C-terminal domain. The structure reveals an unexpected SmAP3 14-mer that, is perforated by a cylindrical pore and is bound to 14 cadmium (Cd(2+)), ions. Individual heptamers adopt either "apical" or "equatorial", conformations that chelate Cd(2+) differently. SmAP3 forms supraheptameric, oligomers (SmAP3)(n = 7,14,28) in solution, and assembly of the asymmetric, 14-mer is modulated by differential divalent cation-binding in apical and, equatorial subunits. Phylogenetic and sequence analyses substantiate, SmAP3s as a unique subset of SmAPs. These results distinguish SmAP3s from, other Sm proteins and provide a model for the structure and properties of, Sm proteins >100 residues in length, e.g., several human Sm proteins.

About this Structure

1M5Q is a Single protein structure of sequence from Pyrobaculum aerophilum with CD, NA, GOL and ACY as ligands. Full crystallographic information is available from OCA.

Reference

Structure and assembly of an augmented Sm-like archaeal protein 14-mer., Mura C, Phillips M, Kozhukhovsky A, Eisenberg D, Proc Natl Acad Sci U S A. 2003 Apr 15;100(8):4539-44. Epub 2003 Mar 31. PMID:12668760

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