Cloning, molecular characterization and heterologous expression of AMY1, an alpha-amylase gene from Cryptococcus flavus

FEMS Microbiol Lett. 2008 Mar;280(2):189-94. doi: 10.1111/j.1574-6968.2007.01059.x. Epub 2008 Feb 12.

Abstract

A Cryptococcus flavus gene (AMY1) encoding an extracellular alpha-amylase has been cloned. The nucleotide sequence of the cDNA revealed an ORF of 1896 bp encoding for a 631 amino acid polypeptide with high sequence identity with a homologous protein isolated from Cryptococcus sp. S-2. The presence of four conserved signature regions, (I) (144)DVVVNH(149), (II) (235)GLRIDSLQQ(243), (III) (263)GEVFN(267), (IV) (327)FLENQD(332), placed the enzyme in the GH13 alpha-amylase family. Furthermore, sequence comparison suggests that the C. flavusalpha-amylase has a C-terminal starch-binding domain characteristic of the CBM20 family. AMY1 was successfully expressed in Saccharomyces cerevisiae. The time course of amylase secretion in S. cerevisiae resulted in a maximal extracellular amylolytic activity (3.93 U mL(-1)) at 60 h of incubation. The recombinant protein had an apparent molecular mass similar to the native enzyme (c. 67 kDa), part of which was due to N-glycosylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Cryptococcus / enzymology
  • Cryptococcus / genetics*
  • Gene Expression Regulation, Fungal
  • Molecular Sequence Data
  • Saccharomyces cerevisiae / genetics
  • alpha-Amylases / chemistry*
  • alpha-Amylases / genetics*
  • alpha-Amylases / metabolism

Substances

  • alpha-Amylases