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Applied Microbiology and Biotechnology

, Volume 56, Issue 3–4, pp 395–401 | Cite as

Chitinase from Bacillus thuringiensis subsp. pakistani

  •  S. Thamthiankul
  •  S. Suan-Ngay
  •  S. Tantimavanich
  •  W. Panbangred
Original Paper

Abstract.

The chitinase gene (chiA71) from Bacillus thuringiensis subsp. pakistani consists of an open reading frame of 1,905 nucleotides encoding 635 amino acid residues with an estimated molecular mass of 71 kDa. Comparison of the deduced amino acid sequence of the mature enzyme to other microbial chitinases shows a putative catalytic domain and a region with conserved amino acids similar to that of the type III module of fibronectin and a chitin-binding domain. By activity detection of chitinase on SDS-PAGE after renaturation, the molecular mass of protein bands with chitinase activity were 66, 60, 47, and 32 kDa. The N-terminal amino acid sequence of each chitinase activity band was the same (Asp-Ser-Pro-Lys-Gln), suggesting that the 60-, 47-, and 32-kDa chitinases were derived from the 66-kDa chitinase by processing step(s) at the C-terminus. The enzyme was identified as an exochitinase, since it generated N-acetylglucosamine from early stage of colloidal chitin hydrolysis. The crude protein (2.3–18.4 mg/ml), containing chitinase at final activities of 8, 16, 32, and 64 mU/ml, was toxic to Aedes aegypti larvae and caused mortalities of 7.5, 15.0, 51.3, and 70.0% respectively, but the same amount of crude protein from a B. thuringiensis subsp. pakistani mutant lacking chitinase was not toxic.

Keywords

Molecular Mass Chitin Crude Protein Chitinase Deduce Amino Acid Sequence 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  •  S. Thamthiankul
    • 1
  •  S. Suan-Ngay
    • 1
  •  S. Tantimavanich
    • 2
  •  W. Panbangred
    • 1
  1. 1.Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
  2. 2.Department of Clinical Microbiology, Faculty of Medical Technology, Mahidol University, Bangkok-Noi District, Bangkok 10700, Thailand

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