TY - JOUR
KW - cyclomaltodextrinase
KW - glycoside hydrolase family 13
KW - Anoxybacillus
KW - Laceyella
AU - Pernilla Turner
AU - Antje Labes
AU - Olafur Fridjonsson
AU - Gudmundur Hreggvidson
AU - Peter Schönheit
AU - Jakob Kristjansson
AU - Olle Holst
AU - Karlsson Nordberg
AB - In this paper, we present the expression and characterization of two novel enzymes from the \ensuremath\alpha-amylase family exhibiting cyclomaltodextrinase specificity. The nucleotide sequences encoding the enzymes were isolated from the genomic DNA of two thermophilic bacterial strains originating from Icelandic hot springs and belonging to the genera Anoxybacillus (AfCda13) and Laceyella (LsCda13). The genes were amplified using a consensus primer strategy utilizing two of the four conserved regions present in glycoside hydrolase family 13. No identifiable signal peptides were present in open reading frames encoding the enzymes, indicating an intracellular location of both enzymes, and their physiological function to be intracellular cyclodextrin degradation. The domain structures of both enzymes were also similar, including an N-terminal domain, the catalytic module composed of the A- and B-domains, and a C-terminal domain. Despite the similarity in domain composition, the two enzymes displayed differences in the oligomeric state with AfCda13 being a dimeric protein, whereas LsCda13 was monomeric. The two enzymes also displayed significantly different activity profiles, despite being active on the same range of substrates. It was shown that the enzyme displaying the highest activity on cyclodextrin was dimeric (AfCda13). Moreover, a fraction of the dimeric enzyme could be converted to a monomeric state in the presence of KCl and this fraction retained only 23\% of its activity on \ensuremath\alpha-cyclodextrin while its activity on starch was not significantly affected, indicating that the oligomeric state is an important factor for a high activity on cyclodextrin substrates.
BT - Journal of Bioscience and Bioengineering
M1 - 4
N2 - In this paper, we present the expression and characterization of two novel enzymes from the \ensuremath\alpha-amylase family exhibiting cyclomaltodextrinase specificity. The nucleotide sequences encoding the enzymes were isolated from the genomic DNA of two thermophilic bacterial strains originating from Icelandic hot springs and belonging to the genera Anoxybacillus (AfCda13) and Laceyella (LsCda13). The genes were amplified using a consensus primer strategy utilizing two of the four conserved regions present in glycoside hydrolase family 13. No identifiable signal peptides were present in open reading frames encoding the enzymes, indicating an intracellular location of both enzymes, and their physiological function to be intracellular cyclodextrin degradation. The domain structures of both enzymes were also similar, including an N-terminal domain, the catalytic module composed of the A- and B-domains, and a C-terminal domain. Despite the similarity in domain composition, the two enzymes displayed differences in the oligomeric state with AfCda13 being a dimeric protein, whereas LsCda13 was monomeric. The two enzymes also displayed significantly different activity profiles, despite being active on the same range of substrates. It was shown that the enzyme displaying the highest activity on cyclodextrin was dimeric (AfCda13). Moreover, a fraction of the dimeric enzyme could be converted to a monomeric state in the presence of KCl and this fraction retained only 23\% of its activity on \ensuremath\alpha-cyclodextrin while its activity on starch was not significantly affected, indicating that the oligomeric state is an important factor for a high activity on cyclodextrin substrates.
PY - 2005
SP - 380
EP - 390
T2 - Journal of Bioscience and Bioengineering
TI - Two novel cyclodextrin-degrading enzymes isolated from thermophilic bacteria, have similar domain structures but different oligomeric states and activity profiles
UR - http://oceanrep.geomar.de/168/
VL - 100
ER -