PMID- 10329152
OWN - NLM
STAT- MEDLINE
DCOM- 19990611
LR  - 20161124
IS  - 0022-2836 (Print)
IS  - 0022-2836 (Linking)
VI  - 288
IP  - 3
DP  - 1999 May 7
TI  - Human glutathione transferase A4-4 crystal structures and mutagenesis reveal the 
      basis of high catalytic efficiency with toxic lipid peroxidation products.
PG  - 427-39
AB  - The oxidation of lipids and cell membranes generates cytotoxic compounds
      implicated in the etiology of aging, cancer, atherosclerosis, neurodegenerative
      diseases, and other illnesses. Glutathione transferase (GST) A4-4 is a key
      component in the defense against the products of this oxidative stress because,
      unlike other Alpha class GSTs, GST A4-4 shows high catalytic activity with lipid 
      peroxidation products such as 4-hydroxynon-2-enal (HNE). The crystal structure of
      human apo GST A4-4 unexpectedly possesses an ordered C-terminal alpha-helix,
      despite the absence of any ligand. The structure of human GST A4-4 in complex
      with the inhibitor S-(2-iodobenzyl) glutathione reveals key features of the
      electrophilic substrate-binding pocket which confer specificity toward HNE. Three
      structural modules form the binding site for electrophilic substrates and thereby
      govern substrate selectivity: the beta1-alpha1 loop, the end of the alpha4 helix,
      and the C-terminal alpha9 helix. A few residue changes in GST A4-4 result in
      alpha9 taking over a predominant role in ligand specificity from the N-terminal
      loop region important for GST A1-1. Thus, the C-terminal helix alpha9 in GST A4-4
      provides pre-existing ligand complementarity rather than acting as a flexible cap
      as observed in other GST structures. Hydrophobic residues in the alpha9 helix,
      differing from those in the closely related GST A1-1, delineate a hydrophobic
      specificity canyon for the binding of lipid peroxidation products. The role of
      residue Tyr212 as a key catalytic residue, suggested by the crystal structure of 
      the inhibitor complex, is confirmed by mutagenesis results. Tyr212 is positioned 
      to interact with the aldehyde group of the substrate and polarize it for
      reaction. Tyr212 also coopts part of the binding cleft ordinarily formed by the
      N-terminal substrate recognition region in the homologous enzyme GST A1-1 to
      reveal an evolutionary swapping of function between different recognition
      elements. A structural model of catalysis is presented based on these results.
CI  - Copyright 1999 Academic Press.
FAU - Bruns, C M
AU  - Bruns CM
AD  - Department of Molecular Biology MB4, Skaggs Institute for Chemical Biology, The
      Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
FAU - Hubatsch, I
AU  - Hubatsch I
FAU - Ridderstrom, M
AU  - Ridderstrom M
FAU - Mannervik, B
AU  - Mannervik B
FAU - Tainer, J A
AU  - Tainer JA
LA  - eng
GR  - F32-AI09937/AI/NIAID NIH HHS/United States
GR  - GM39345/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - J Mol Biol
JT  - Journal of molecular biology
JID - 2985088R
RN  - 0 (Aldehydes)
RN  - 0 (DNA Primers)
RN  - 0 (Isoenzymes)
RN  - 42HK56048U (Tyrosine)
RN  - EC 2.5.1.18 (Glutathione Transferase)
RN  - GAN16C9B8O (Glutathione)
RN  - K1CVM13F96 (4-hydroxy-2-nonenal)
RN  - TE7660XO1C (Glycine)
SB  - IM
MH  - Aldehydes/metabolism
MH  - Amino Acid Sequence
MH  - Base Sequence
MH  - Binding Sites
MH  - Catalysis
MH  - Crystallography, X-Ray
MH  - DNA Primers
MH  - Glutathione/metabolism
MH  - Glutathione Transferase/*chemistry/genetics/metabolism
MH  - Glycine/metabolism
MH  - Humans
MH  - Isoenzymes/*chemistry/genetics/metabolism
MH  - *Lipid Peroxidation
MH  - Models, Molecular
MH  - Molecular Sequence Data
MH  - Mutagenesis
MH  - Protein Conformation
MH  - Sequence Homology, Amino Acid
MH  - Tyrosine/metabolism
EDAT- 1999/05/18 00:00
MHDA- 1999/05/18 00:01
CRDT- 1999/05/18 00:00
PHST- 1999/05/18 00:00 [pubmed]
PHST- 1999/05/18 00:01 [medline]
PHST- 1999/05/18 00:00 [entrez]
AID - S0022-2836(99)92697-9 [pii]
AID - 10.1006/jmbi.1999.2697 [doi]
PST - ppublish
SO  - J Mol Biol. 1999 May 7;288(3):427-39. doi: 10.1006/jmbi.1999.2697.