Premium
The thermal adaptation of the nitrogenase Fe protein from thermophilic Methanobacter thermoautotrophicus
Author(s) -
Sen Sanchayita,
Peters John W.
Publication year - 2005
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20765
Subject(s) - azotobacter vinelandii , nitrogenase , thermophile , chemistry , protein structure , macromolecular crowding , biochemistry , biophysics , macromolecule , crystallography , nitrogen fixation , biology , enzyme , nitrogen , organic chemistry
The nitrogenase Fe protein is a key component of the biochemical machinery responsible for the process of biological nitrogen fixation. The Fe protein is a member of a class of nucleotide‐binding proteins that couple the binding and hydrolysis of nucleoside triphosphates to conformational changes. The nucleotide‐dependent conformational changes modulate the formation of a macromolecular complex, and some members of the class include Gα, EF‐Tu, and myosin. The members of this class are highly interesting model systems for the analysis of aspects of thermal adaptability, since their mechanisms involve protein conformational change and protein–protein interactions. In this study, we have used our extensive knowledge of the structure of the Azotobacter vinelandii nitrogenase Fe protein in multiple structural conformations, and standard homology modeling approaches have been used to generate reliable models of the Fe protein from thermophilic Methanobacter thermoautotrophicus in the analogous structural conformations. The resulting structural comparison reveals that thermal adaptation of the M. thermoautotrophicus Fe protein is conferred by a number of factors, including increased structural rigidity that results from various structural changes within the protein interior. The analysis of hypothetical docking models and nitrogenase complex structures provides insights into the thermal adaptation of the protein–protein interactions that support macromolecular complex formation and catalysis at higher temperatures. Proteins 2006. © 2005 Wiley‐Liss, Inc.