2bwd

Publication Abstract from PubMed

Copper-containing nitrite reductases catalyze the reduction of nitrite to nitric oxide (NO), a key step in denitrification that results in the loss of terrestrial nitrogen to the atmosphere. They are found in a wide variety of denitrifying bacteria and fungi of different physiology from a range of soil and aquatic ecosystems. Structural analysis of potential intermediates in the catalytic cycle is an important goal in understanding enzyme mechanism. Using "crystal harvesting" and substrate-soaking techniques, we have determined atomic resolution structures of four forms of the green Cu-nitrite reductase, from the soil bacterium Achromobacter cycloclastes. These structures are the resting state of the enzyme at 0.9 A, two species exhibiting different conformations of nitrite bound at the catalytic type 2 Cu, one of which is stable and also has NO present, at 1.10 A and 1.15 A, and a stable form with the product NO bound side-on to the catalytic type 2 Cu, at 1.12 A resolution. These structures provide incisive insights into the initial binding of substrate, its repositioning before catalysis, bond breakage (O-NO), and the formation of a stable NO adduct.

Atomic resolution structures of resting-state, substrate- and product-complexed Cu-nitrite reductase provide insight into catalytic mechanism.,Antonyuk SV, Strange RW, Sawers G, Eady RR, Hasnain SS Proc Natl Acad Sci U S A. 2005 Aug 23;102(34):12041-6. Epub 2005 Aug 10. PMID:16093314^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.