1j99

From Proteopedia

Revision as of 11:20, 21 February 2008

CRYSTAL STRUCTURE OF HUMAN DEHYDROEPIANDROSTERONE SULFOTRANSFERASE IN COMPLEX WITH SUBSTRATE

Overview

Dehydroepiandrosterone sulphotransferase (DHEA-ST) is an enzyme that converts dehydroepiandrosterone (DHEA), and some other steroids, into their sulphonated forms. The enzyme catalyses the sulphonation of DHEA on the 3alpha-oxygen, with 3'-phosphoadenosine-5'-phosphosulphate contributing the sulphate. The structure of human DHEA-ST in complex with its preferred substrate DHEA has been solved here to 1.99 A using molecular replacement with oestradiol sulphotransferase (37% sequence identity) as a model. Two alternative substrate-binding orientations have been identified. The primary, catalytic, orientation has the DHEA 3alpha-oxygen and the highly conserved catalytic histidine in nearly identical positions as are seen for the related oestradiol sulphotransferase. The substrate, however, shows rotations of up to 30 degrees, and there is a corresponding rearrangement of the protein loops contributing to the active site. This may also reflect the low identity between the two enzymes. The second orientation penetrates further into the active site and can form a potential hydrogen bond with the desulphonated cofactor 3',5'-phosphoadenosine (PAP). This second site contains more van der Waal interactions with hydrophobic residues than the catalytic site and may also reflect the substrate-inhibition site. The PAP position was obtained from the previously solved structure of DHEA-ST co-crystallized with PAP. This latter structure, due to the arrangement of loops within the active site and monomer interactions, cannot bind substrate. The results presented here describe details of substrate binding to DHEA-ST and the potential relationship to substrate inhibition.

Disease

Known diseases associated with this structure: Histidinemia OMIM:[609457], Selective T-cell defect OMIM:[176947]

About this Structure

1J99 is a Single protein structure of sequence from Homo sapiens with , and as ligands. Active as Alcohol sulfotransferase, with EC number 2.8.2.2 Full crystallographic information is available from OCA.

Reference

Crystal structure of human dehydroepiandrosterone sulphotransferase in complex with substrate., Rehse PH, Zhou M, Lin SX, Biochem J. 2002 May 15;364(Pt 1):165-71. PMID:11988089

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