The Protein Journal

, Volume 29, Issue 6, pp 440–444 | Cite as

Residue 544 in Domain III of the Bacillus thuringiensis Cry1Ac Toxin is Involved in Protein Structure Stability



A unique residue W544 in the β18–β19 loop of the Bacillus thuringiensis Cry1Ac toxin has been implicated in its toxicity. In this study, the effects of mutations at this residue on protein stability during protease treatment, UV irradiation, and preservation were examined. Residue 544 of Cry1Ac was involved in maintaining structural stability, and substitution of a polar group at this position was unfavorable to protein stability. One mutant, W544F, produced larger crystals and was more stable. This mutant showed greater resistance to UV radiation than the wild type Cry1Ac but retained equal toxicity. This is the first report showing that residue 544 in the Cry1Ac domain III plays a significant role in toxin structural stability. Our W544F mutant is a significant development in terms of field applications of Cry1Ac toxin.


Bacillus thuringiensis Stability Proteolysis UV irradiation Tryptophan 



Bacillus thuringiensis


Insecticidal crystal protein






Sodium dodecyl sulfate polyacrylamide gel electrophoresis


Atomic force microscope



We thank Mr. Shan Shiping for technical assistance of AFM. This work was supported in part by 863 grants (2008AA100801, 2006AA02Z187, 2006AA10212) and a grant from the Ph.D. Programs Foundation of Ministry of Education of China (20060452006).


  1. 1.
    Boonserm P, Davis P, Ellar DJ, Li J (2005) J Mol Biol 348:363–382CrossRefGoogle Scholar
  2. 2.
    Boonserm P, Mo M, Angsuthanasombat C, Lescar J (2006) J Bacteriol 188:3391–3401CrossRefGoogle Scholar
  3. 3.
    Bravo A, Gill SS, Soberon M (2006) Toxicon 49:423–435CrossRefGoogle Scholar
  4. 4.
    Dean DH, Rajamohan F, Lee MK, Wu SJ, Chen XJ, Alcantara E, Hussain SR (1996) Gene 179:111–117CrossRefGoogle Scholar
  5. 5.
    Galitsky N, Cody V, Wojtczak A, Ghosh D, Luft JR, Pangborn W, English L (2001) Acta Crystallogr D Biol Crystallogr 57:1101–1109CrossRefGoogle Scholar
  6. 6.
    Grochulski P, Masson L, Borisova S, Pusztai-Carey M, Schwartz JL, Brousseau R, Cygler M (1995) J Mol Biol 254:447–464CrossRefGoogle Scholar
  7. 7.
    Hu SB, Liu P, Ding XZ, Yan L, Sun YJ, Zhang YM, Li WP, Xia LQ (2009) Appl Microbiol Biotechnol 82:1157–1167CrossRefGoogle Scholar
  8. 8.
    Laflamme E, Badia A, Lafleur M, Schwartz JL, Laprade R (2008) J Membr Biol 222:127–139CrossRefGoogle Scholar
  9. 9.
    Li J, Carroll J, Ellar DJ (1991) Nature 53:815–821CrossRefGoogle Scholar
  10. 10.
    Masson L, Tabashnik BE, Mazza A, Préfontaine G, Potvin L, Brousseau R, Schwartz JL (2002) Appl Environ Microbiol 68:194–200CrossRefGoogle Scholar
  11. 11.
    Morse RJ, Yamamoto T, Stroud RM (2001) Structure (Camb) 9:409–417CrossRefGoogle Scholar
  12. 12.
    Nishimoto T, Yoshisue H, Ihara K, Sakai H, Komano T (1994) FEBS Lett 48:249–254CrossRefGoogle Scholar
  13. 13.
    Padilla C, Pardo-López L, de la Riva G, Gómez I, Sánchez J, Hernandez G, Nuñez ME, Carey MP, Dean DH, Alzate O, Soberón M, Bravo A (2006) Appl Environ Microbiol 72:901–907CrossRefGoogle Scholar
  14. 14.
    Pozsgay M, Fast P, Kaplan H, Carey PR (1987) J Invertebr Pathol 50:246–253CrossRefGoogle Scholar
  15. 15.
    Schnepf E, Crickmore N, Van Rie J, Lereclus D, Baum J, Feitelson J, Zeigler DR, Dean DH (1998) Microbiol Mol Biol Rev 62:775–806Google Scholar
  16. 16.
    Seale JW (2006) Proteins 63:385–390CrossRefGoogle Scholar
  17. 17.
    Wang FX, Xia LQ, Zhao XM, Lv Y, Yu ZQ (2009) J Invertebr Pathol 101:119–123CrossRefGoogle Scholar
  18. 18.
    Xia LQ, Wang FX, Ding XZ, Zhao XM, Fu ZJ, Quan MF, Yu ZN (2008) Chin Sci Bull 53:3178–3184CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  1. 1.College of Chemistry and BioengineeringChangsha University of Science and TechnologyChangshaChina
  2. 2.College of Life Science and TechnologyCentral South Forestry UniversityChangshaChina
  3. 3.Key Lab of Microbial Molecular Biology of Hunan Province, College of Life ScienceHunan Normal UniversityChangshaChina

Personalised recommendations