1r27
From Proteopedia
Crystal Structure of NarGH complex
Overview
The structure of the catalytic and electron-transfer subunits (NarGH) of the integral membrane protein, respiratory nitrate reductase (Nar) has been determined to 2.0 A resolution revealing the molecular architecture of this Mo-bisMGD (molybdopterin-guanine-dinucleotide) containing enzyme which includes a previously undetected FeS cluster. Nar, together with the related enzyme formate dehydrogenase (Fdh-N), is a key enzyme in the generation of proton motive force across the membrane in Escherichia coli nitrate respiration. A comparative study revealed that Nar and Fdh-N employ different approaches for acquiring substrate, reflecting different catalytic mechanisms. Nar uses a very narrow and nonpolar substrate-conducting cavity with a nonspecific substrate binding site, whereas Fdh-N accommodates a wider, positively charged substrate-conducting cavity with a more specific substrate binding site. The Nar structure also demonstrates the first example of an Asp side chain acting as a Mo ligand providing a structural basis for the classification of Mo-bisMGD enzymes.
About this Structure
1R27 is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Architecture of NarGH reveals a structural classification of Mo-bisMGD enzymes., Jormakka M, Richardson D, Byrne B, Iwata S, Structure. 2004 Jan;12(1):95-104. PMID:14725769 Page seeded by OCA on Sat May 3 06:59:05 2008
