1qoi

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Template:STRUCTURE 1qoi

U4/U6 SNRNP-SPECIFIC CYCLOPHILIN SNUCYP-20

Overview

The cyclophilin SnuCyp-20 is a specific component of the human U4/U6 small nuclear ribonucleoprotein particle involved in the nuclear splicing of pre-mRNA. It stably associates with the U4/U6-60kD and -90kD proteins, the human orthologues of the Saccharomyces cerevisiae Prp4 and Prp3 splicing factors. We have determined the crystal structure of SnuCyp-20 at 2.0-A resolution by molecular replacement. The structure of SnuCyp-20 closely resembles that of human cyclophilin A (hCypA). In particular, the catalytic centers of SnuCyp-20 and hCypA superimpose perfectly, which is reflected by the observed peptidyl-prolyl-cis/trans-isomerase activity of SnuCyp-20. The surface properties of both proteins, however, differ significantly. Apart from seven additional amino-terminal residues, the insertion of five amino acids in the loop alpha1-beta3 and of one amino acid in the loop alpha2-beta8 changes the conformations of both loops. The enlarged loop alpha1-beta3 is involved in the formation of a wide cleft with predominantly hydrophobic character. We propose that this enlarged loop is required for the interaction with the U4/U6-60kD protein.

About this Structure

1QOI is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Crystal structure of the human U4/U6 small nuclear ribonucleoprotein particle-specific SnuCyp-20, a nuclear cyclophilin., Reidt U, Reuter K, Achsel T, Ingelfinger D, Luhrmann R, Ficner R, J Biol Chem. 2000 Mar 17;275(11):7439-42. PMID:10713041 Page seeded by OCA on Sat May 3 06:31:07 2008