3K1A

Insights into substrate binding at FeMo-cofactor in nitrogenase from the structure of an alpha-70Ile MoFe protein variant

3K1A の概要

• エントリーDOI: 10.2210/pdb3k1a/pdb
• 分子名称: Nitrogenase molybdenum-iron protein alpha chain, Nitrogenase molybdenum-iron protein beta chain, 3-HYDROXY-3-CARBOXY-ADIPIC ACID, ... (7 entities in total)
• 機能のキーワード: nitrogen fixation, mofe protein, nitrogenase, isoleucine, proton reduction, nitrogen, acetylene, hydride reduction, atp-binding, iron, iron-sulfur, metal-binding, nucleotide-binding, oxidoreductase, molybdenum
• 由来する生物種: Azotobacter vinelandii; 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 232714.90

構造登録者

Peters, J.W.,Sarma, R.,Barney, B.M.,Keable, S.,Seefeldt, L.C.,Dean, D.R. (登録日: 2009-09-26, 公開日: 2010-02-16, 最終更新日: 2023-09-06)

主引用文献

Sarma, R.,Barney, B.M.,Keable, S.,Dean, D.R.,Seefeldt, L.C.,Peters, J.W.
Insights into substrate binding at FeMo-cofactor in nitrogenase from the structure of an alpha-70(Ile) MoFe protein variant
J.Inorg.Biochem., 104:385-389, 2010

PubMed Abstract: The X-ray crystal structure is presented for a nitrogenase MoFe protein where the alpha subunit residue at position 70 (alpha-70(Val)) has been substituted by the amino acid isoleucine (alpha-70(Ile)). Substitution of alpha-70(Val) by alpha-70(Ile) results in a MoFe protein that is hampered in its ability to reduce a range of substrates including acetylene and N(2), yet retains normal proton reduction activity. The 2.3A structure of the alpha-70(Ile) MoFe protein is compared to the alpha-70(Val) wild-type MoFe protein, revealing that the delta methyl group of alpha-70(Val) is positioned over Fe6 within the active site FeMo-cofactor. This work provides strong crystallographic support for the previously proposed model that substrates bind and are reduced at a single 4Fe-4S face of the FeMo-cofactor and that when alpha-70(Val) is substituted by alpha-70(Ile) access of substrates to Fe6 of this face is effectively blocked. Furthermore the detailed examination of the structure provides the basis for understanding the ability to trap and characterize hydrides in the variant, contributing significantly to our understanding of substrate access and substrate reduction at the FeMo-cofactor active site of nitrogenase.

PubMed: 20022118
DOI: 10.1016/j.jinorgbio.2009.11.009

実験手法

X-RAY DIFFRACTION (2.23 Å)