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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2000-10-18
pubmed:abstractText
The gene for a 104-kDa exocellulase, Cel48A, formerly E6, was cloned from Thermobifida fusca into Escherichia coli and Streptomyces lividans. The DNA sequence revealed a type II cellulose-binding domain at the N-terminus, followed by a FNIII-like domain and ending with a glycosyl hydrolase Family 48 catalytic domain. The enzyme and catalytic domain alone were each expressed in and purified from S. lividans and had very low catalytic activity on swollen cellulose, carboxymethyl cellulose, bacterial microcrystalline cellulose and filter paper. However, in synergistic assays on filter paper, the addition of Cel48A to a balanced mixture of T. fusca endocellulase and exocellulase increased the specific activity from 7.9 to 11.7 micromol cellobiose.min-1.mL-1, more than 15-fold higher than any single enzyme alone. Cel48A retained > 50% of its maximum activity from pH 5 to 9 and from 40 to 60 degrees C. Using SWISSMODEL, the amino-acid sequence of the Cel48Acd was modeled to the known structure of Clostridium cellulolyticum CelF. Family 48 enzymes are remarkably homologous at 35% identity for all their catalytic domains and some of the properties of the 10 members are discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0014-2956
pubmed:author
pubmed:issnType
Print
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4988-97
pubmed:dateRevised
2007-7-23
pubmed:meshHeading
pubmed-meshheading:10931180-Actinomycetales, pubmed-meshheading:10931180-Amino Acid Sequence, pubmed-meshheading:10931180-Base Sequence, pubmed-meshheading:10931180-Catalytic Domain, pubmed-meshheading:10931180-Cellulase, pubmed-meshheading:10931180-Cellulose 1,4-beta-Cellobiosidase, pubmed-meshheading:10931180-Cloning, Molecular, pubmed-meshheading:10931180-Clostridium, pubmed-meshheading:10931180-Escherichia coli, pubmed-meshheading:10931180-Isoenzymes, pubmed-meshheading:10931180-Kinetics, pubmed-meshheading:10931180-Molecular Sequence Data, pubmed-meshheading:10931180-Recombinant Proteins, pubmed-meshheading:10931180-Restriction Mapping, pubmed-meshheading:10931180-Sequence Alignment, pubmed-meshheading:10931180-Sequence Homology, Amino Acid, pubmed-meshheading:10931180-Streptomyces, pubmed-meshheading:10931180-Substrate Specificity, pubmed-meshheading:10931180-Thermodynamics
pubmed:year
2000
pubmed:articleTitle
Cloning, expression and characterization of a family 48 exocellulase, Cel48A, from Thermobifida fusca.
pubmed:affiliation
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't