2h8k

From Proteopedia

Revision as of 13:14, 23 March 2008

Human Sulfotranferase SULT1C3 in complex with PAP

Overview

Cytosolic sulfotransferases sulfate steroids such as estrogens and hydroxysteroids. The enzymes, including human estrogen sulfotransferase (hEST) and hydroxysteroid sulfotransferase (hHST), are generally homodimers in solution with mouse estrogen sulfotransferase (mEST) being one of few exceptions. To identify the amino acid residues responsible for the dimerization, eight residues on the surface of hEST were mutated to their counterparts in mEST and mutated hESTs were then analyzed by gel filtration chromatography. A single mutation of Val(269) to Glu was sufficient to convert hEST to a monomer and the corresponding mutation of Val(260) also altered hHST to a monomer. The hHST crystal structure revealed a short stretch of peptide with the side-chains from two hHST monomers forming a hydrophobic zipper-like structure enforced by ion pairs at both ends. This peptide consisted of 10 residues near the C-terminus that, including the critical Val residue, is conserved as KXXXTVXXXE in nearly all cytosolic sulfotransferases. When mEST underwent the double mutations Pro269Thr/Glu270Val dimerization resulted. Thus, the KXXXTVXXXE sequence appears to be the common protein-protein interaction motif that mediates the homo- as well as heterodimerization of cytosolic sulfotransferases.

About this Structure

2H8K is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

The dimerization motif of cytosolic sulfotransferases., Petrotchenko EV, Pedersen LC, Borchers CH, Tomer KB, Negishi M, FEBS Lett. 2001 Feb 9;490(1-2):39-43. PMID:11172807

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