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Data Evaluation Record - Food Allergenicity - Amino Acid Sequence Homology MRID NO: 44384404
Date: 4/8/98
Reviewed by: John L. Kough,
Ph.D., Biologist, BPPD
Secondary Reviewer: Doug Gurian-Sherman, Ph.D., Plant Pathologist,
BPPD
STUDY TYPE: Food Allergenicity- Amino Acid Sequence Homology
MRID NO: 44384404
CHEMICAL NO: 006466- Bacillus thuringiensis subsp. tolworthi Cry9C toxin
TEST MATERIAL: Presumed amino acid sequence of Cry9C
STUDY NO: none assigned
SPONSOR: Plant Genetic Systems (America) Inc., Des Moines, IA
TEST FACILITY: Plant Genetic Systems NV, Ghent, Belgium
TITLE OF REPORT: Cry9C Bacillus thuringiensis Insecticidal Protein Identification of Sequence Homology with Allergenicity by Searching Protein Databanks
AUTHOR: Marnix Peferoen
STUDY COMPLETED: September 12, 1997
CONCLUSION: Sequence identity for any of the eight amino acid regions in Cry9C was found only to other Bt crystal proteins. No match between any 8 amino acid sequence in Cry9C and any of the allergenic proteins known in the SWISS protein database was found. This lack of homology at a finer level of examination is further evidence that Cry9C is not related to known allergens using a structural consensus approach.
CLASSIFICATION: SUPPLEMENTAL. BPPD has not yet determined how to judge amino acid homology for risk assessment purposes. No further studies need to be done at this time for analyzing homology.
STUDY DESIGN
A homology comparison was done utilizing a sequential series of 8 amino acids of the Cry9C protein against the sequences from known proteins to assess the similarity of any given 8 amino acids in Cry9c to known allergens. No laboratory work is included and the study is not considered applicable to GLP standards.
TEST METHODS
Test Substance:
DNA sequence of Cry9C analyzed as a stepwise series of overlapping 8 amino acids.
Test System:
The FASTDB software from European Bio-informatics Institute was used to screen the SWISS protein databank.
RESULTS AND DISCUSSION
Similar to the previous homology analysis, sequence identity for any of the eight amino acid regions in Cry9C was found only to other Bt crystal proteins. No match between any 8 amino acid sequence in Cry9C and any of the allergenic proteins known in the SWISS protein database was found. This lack of homology at a finer level of examination is further evidence that Cry9C is not related to known allergens using a structural consensus approach.