Functional analysis of block 5, one of the highly conserved amino acid sequences in the 130-kDa CryIVA protein produced by Bacillus thuringiensis subsp. israelensis.
There are five amino acid sequences highly conserved among Bacillus thuringiensis delta-endotoxins. We have changed the amino acid residues in block 5, one of the conserved sequences, of CryIVA. When the amino acid residues with charged side chains were replaced by others, the amount of production of the altered CryIVA protein was markedly decreased. It is suggested that the decrease is caused by the unstable conformation of the altered CryIVA protein molecule, as judged by digestion with trypsin and thermolysin. On the other hand, the substitution of amino acid residues in block 5 did not affect the insecticidal activity of CryIVA. These results strongly suggest that block 5 of CryIVA is one of the stability-determining elements of the protoxin molecule.
Nishimoto
T
T
Department of Agricultural Chemistry, Faculty of Agriculture, Kyoto University, Japan.
Yoshisue
H
H
Ihara
K
K
Sakai
H
H
Komano
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D001427:Bacterial Toxins; D001483:Base Sequence; D017124:Conserved Sequence; D009033:Culicidae / Q000187:drug effects; D004355:Drug Stability; D004731:Endotoxins; D006460:Hemolysin Proteins; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology; D010572:Pest Control, Biological; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013820:Thermolysin / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D010446:Peptide Fragments; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D014357:Trypsin; D013820:Thermolysin