α-Lys⁴²⁴ Participates in Insertion of FeMoco to MoFe Protein and Maintains Nitrogenase Activity in Klebsiella oxytoca M5al.

ABSTRACT: Our previous investigation of substrates reduction catalyzed by nitrogenase suggested that α-Ile⁴²³ of MoFe protein possibly functions as an electron transfer gate to Mo site of active center-"FeMoco". Amino acid residue α-Lys⁴²⁴ connects directly to α-Ile⁴²³, and they are located in the same α-helix (α423-431). In the present study, function of α-Lys⁴²⁴ was investigated by replacing it with Arg (alkaline, like Lys), Gln (neutral), Glu (acidic), and Ala (neutral) through site-directed mutagenesis and homologous recombination. The mutants were, respectively, termed 424R, 424Q, 424E, and 424A. Studies of diazotrophic cell growth, cytological, and enzymatic properties indicated that none of the substitutions altered the secondary structure of MoFe p

SUBMITTER: Song L 

PROVIDER: S-EPMC6477116 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature