4wes

Publication Abstract from PubMed

The X-ray crystal structure of the nitrogenase MoFe protein from Clostridium pasteurianum (Cp1) has been determined at 1.08 A resolution by multiwavelength anomalous diffraction phasing. Cp1 and the ortholog from Azotobacter vinelandii (Av1) represent two distinct families of nitrogenases, differing primarily by a long insertion in the alpha-subunit and a deletion in the beta-subunit of Cp1 relative to Av1. Comparison of these two MoFe protein structures at atomic resolution reveals conserved structural arrangements that are significant to the function of nitrogenase. The FeMo cofactors defining the active sites of the MoFe protein are essentially identical between the two proteins. The surrounding environment is also highly conserved, suggesting that this structural arrangement is crucial for nitrogen reduction. The P clusters are likewise similar, although the surrounding protein and solvent environment is less conserved relative to that of the FeMo cofactor. The P cluster and FeMo cofactor in Av1 and Cp1 are connected through a conserved water tunnel surrounded by similar secondary-structure elements. The long alpha-subunit insertion loop occludes the presumed Fe protein docking surface on Cp1 with few contacts to the remainder of the protein. This makes it plausible that this loop is repositioned to open up the Fe protein docking surface for complex formation.

Nitrogenase MoFe protein from Clostridium pasteurianum at 1.08 A resolution: comparison with the Azotobacter vinelandii MoFe protein.,Zhang LM, Morrison CN, Kaiser JT, Rees DC Acta Crystallogr D Biol Crystallogr. 2015 Feb;71(Pt 2):274-82. doi:, 10.1107/S1399004714025243. Epub 2015 Jan 23. PMID:25664737^[1]

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