Critical spacing between two essential cysteine residues in the interdomain linker of the Bradyrhizobium japonicum NifA protein.
A special sequence motif in the Bradyrhizobium japonicum NifA protein, consisting of two functionally essential cysteines separated by four other amino acids (Cys-aa4-Cys), has been proposed to be part of a potential metal-binding site [(1988) Nucleic Acids Res. 16, 2207-2224]. Using the techniques of oligonucleotide-directed mutagenesis, we report here that several of the four intervening amino acids can be replaced by others without loss of NifA function. The deletion of one amino acid to give a Cys-aa3-Cys motif renders the protein inactive whereas the creation of a Cys-aa5-Cys motif (one amino acid inserted) still leads to a partially active NifA protein.
Fischer
H M
HM
Mikrobiologisches Institut, Eidgenössische Technische Hochschule, ETH-Zentrum, Zürich, Switzerland.
Fritsche
S
S
Herzog
B
B
Hennecke
H
H
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics*; D001483:Base Sequence; D003545:Cysteine / Q000032:analysis / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000032:analysis; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009586:Nitrogen Fixation / Q000235:genetics*; D015202:Protein Engineering; D012231:Rhizobium / Q000032:analysis / Q000235:genetics*; D014157:Transcription Factors; D014158:Transcription, Genetic
D000596:Amino Acids; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C061338:NifA protein, Bacteria; D014157:Transcription Factors; D003545:Cysteine