Related Experiment Video
Updated: Jan 27, 2026

Identification of Fatty Acids in Bacillus cereus
Published on: December 5, 2016
The conserved cysteine residues in Bacillus thuringiensis Cry1Ac protoxin are not essential for the bipyramidal
Ran Li1, Sisi Yang1, Xianfeng Qiu1
1College of Life Science, State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Normal University, Changsha 410081, PR China.
Abstract:
To evaluate the function of conserved cysteine residues in Cry1Ac protoxin, we constructed a series of Cry1Ac mutants in which single or multiple cysteine residues were replaced with serine. It was found that cysteine substitution had little effect on the protoxin expression and bipyramidal crystal formation. Bioassays using Plutella xylostella larvae showed that two mutants with fourteen cysteine residues in the C-terminal half and all sixteen residues replaced had similar toxicity as wildtype Cry1Ac protoxin. Our study suggests that the conserved cysteine resudues in the Cry1Ac protoxin are not essential for deposition into a bipyramidal crystal even though the C-terminal half was directly involved in crystal formation.
Related Concept Videos
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
What is Conservation Biology?
Conservation of Small Populations
Residual Stresses
Residual Plots
When the residual values are plotted against the variable x, it is called a residual...
Compounds Essential to Human Function
Inorganic Compounds Essential to Human Functioning
Inorganic compounds essential to human functioning include water, salts, acids, and bases. These compounds are inorganic, i.e., they do not have a carbon-hydrogen bond. Water...

