Crystal structures of zinc-free and -bound heme domain of human inducible nitric-oxide synthase. Implications for dimer stability and comparison with endothelial nitric-oxide synthase.
Primary Citation of Related Structures: 1NSI, 2NSI
PubMed Abstract:
The crystal structures of the heme domain of human inducible nitric-oxide synthase (NOS-2) in zinc-free and -bound states have been solved. In the zinc-free structure, two symmetry-related cysteine residues form a disulfide bond. In the zinc-bound state, these same two cysteine residues form part of a zinc-tetrathiolate (ZnS(4)) center indistinguishable from that observed in the endothelial isoform (NOS-3) ...
The crystal structures of the heme domain of human inducible nitric-oxide synthase (NOS-2) in zinc-free and -bound states have been solved. In the zinc-free structure, two symmetry-related cysteine residues form a disulfide bond. In the zinc-bound state, these same two cysteine residues form part of a zinc-tetrathiolate (ZnS(4)) center indistinguishable from that observed in the endothelial isoform (NOS-3). As in NOS-3, ZnS(4) plays a key role in stabilizing intersubunit contacts and in maintaining the integrity of the cofactor (tetrahydrobiopterin) binding site of NOS-2. A comparison of NOS-2 and NOS-3 structures illustrates the conservation of quaternary structure, tertiary topology, and substrate and cofactor binding sites, in addition to providing insights on isoform-specific inhibitor design. The structural comparison also reveals that pterin binding does not preferentially stabilize the dimer interface of NOS-2 over NOS-3.
Related Citations:
Structure of Nitric Oxide Synthase Oxygenase Dimer with Pterin and Substrate Crane, B.R., Arvai, A.S., Ghosh, D.K., Wu, C., Getzoff, E.D., Stuehr, D.J., Tainer, J.A. (1998) Science 279: 2121
The Structure of Nitric Oxide Synthase Oxygenase Domain and Inhibitor Complex Crane, B.R., Arvai, A.S., Gachhui, R., Wu, C., Ghosh, D.K., Getzoff, E.D., Stuehr, D.J., Tainer, J.A. (1997) Science 278: 425
Crystal Structure of Constitutive Endothelial Nitric Oxide Synthase: A Paradigm for Pterin Function Involving a Novel Metal Center Raman, C.S., Li, H., Martasek, P., Kral, V., Masters, B.S., Poulos, T.L. (1998) Cell 95: 939
Organizational Affiliation:
Department of Molecular Biology and Biochemistry, University of California at Irvine, Irvine, California 92697, USA.
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