The gene encoding the kappa-carrageenase of Alteromonas carrageenovora is related to β-1,3-1,4-glucanases

Abstract

The nucleotide (nt) and deduced amino acid (aa) sequences are reported for the structural gene cgkA encoding K-carrageenase (M, 44 412) from the marine bacterium Alteromonas carrageenovora (ATCC 43555), a hydrolase involved in the degradation of K-carrageenan. The cgkA gene codes for a protein of 397 aa, with a signal peptide of 25 aa. The enzyme is a new member of family 16 of glycosyl hydrolases, which comprises β-1,3-1,4-glucanases from various sources and the β-agarase of Streptomyces coelicolor. It is proposed that residue Glu163 in the K-carrageenase from A. carrageenovora and Glu155 in the β-agarase from S. coelicolor are important for catalysis. © 1994.