High-resolution crystal structure of activated Cyt2Ba monomer from Bacillus thuringiensis subsp. israelensis.
The Cyt family of proteins consists of delta-endotoxins expressed during sporulation of several subspecies of Bacillus thuringiensis. Its members possess insecticidal, hemolytic, and cytolytic activities through pore formation and attract attention due to their potential use as vehicles for targeted membrane destruction. The delta-endotoxins of subsp. israelensis include three Cyt species: a major Cyt1Aa and two minor proteins, Cyt2Ba and Cyt1Ca. A cleaved Cyt protein that lacks the N- and C-terminal segments forms a toxic monomer. Here, we describe the crystal structure of Cyt2Ba, cleaved at its amino and carboxy termini by bacterial endogenous protease(s). Overall, its fold resembles that of the previously described volvatoxin A2 and the nontoxic form of Cyt2Aa. The structural similarity between these three proteins may provide information regarding the mechanism(s) of membrane-perforating toxins.
Department of Life Sciences, Ben-Gurion University of the Negev, POB 653, Be'er-Sheva 84105, Israel. shmulikc@ariel.ac.il
Shmuel
S
Cohen
Orly
O
Dym
Shira
S
Albeck
Eitan
E
Ben-Dov
Rivka
R
Cahan
Michael
M
Firer
Arieh
A
Zaritsky
D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D004731:Endotoxins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006461:Hemolysis; D006801:Humans; D006868:Hydrolysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010572:Pest Control, Biological; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012995:Solubility
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011994:Recombinant Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis