A cold-active salmon goose-type lysozyme with high heat tolerance.
The Atlantic salmon (Salmo salar) goose-type lysozyme gene was isolated and revealed alternative splicing within exon 2 affecting the signal peptide-encoding region. The lysozyme was produced in Escherichia coli, and the recombinant enzyme showed a high specific lytic activity that was stimulated by low or moderate concentrations of mono- or divalent cations. Relative lytic activities of 70 and 100% were measured at 4 degrees C and 22 degrees C, respectively, and there was no detectable activity at 60 degrees C. However, 30% activity was retained after heating the enzyme for 3 h at 90 degrees C. This unique combination of thermal properties was surprising since the salmon goose-type lysozyme contains no cysteines for protein structure stabilization through disulphide bond formation. The results point to a rapid reversal of inactivation, probably due to instant protein refolding.
Kyomuhendo
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P
Marine Biotechnology and Fish Health, Norwegian Institute of Fisheries & Aquaculture, P.O. Box 6122, N-9291 Tromsø, Norway.
Myrnes
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B
Nilsen
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IW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009994:Osmolar Concentration; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020317:Salmo salar / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D011994:Recombinant Proteins; D004247:DNA; D009113:Muramidase