Linked Life Data

10861939

Source:http://linkedlifedata.com/resource/pubmed/id/10861939

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-9-25
pubmed:abstractText
The esterase from the thermophilic eubacterium Bacillus acidocaldarius is a thermophilic and thermostable monomeric protein with a molecular mass of 34 KDa. The enzyme, characterized as a "B-type" carboxylesterase, displays the maximal activity at 65 degrees C. Interestingly, it is also quite active at room temperature, an unusual feature for an enzyme isolated from a thermophilic microorganism. We investigated the effect of temperature on the structural properties of the enzyme, and compared its structural features with those of the esterase from the hyperthermophilic archaeon Archaeoglobus fulgidus. In particular, the secondary structure and the thermal stability of the esterase were studied by FT-IR spectroscopy, while information on the conformational dynamics of the enzyme were obtained by frequency-domain fluorometry and anisotropy decays. Our data pointed out that the Bacillus acidocaldarius enzyme possesses a secondary structure rich in alpha-helices as described for the esterase isolated from Archaeoglobus fulgidus. Moreover, infrared spectra indicated a higher accessibility of the solvent ((2)H(2)O) to Bacillus acidocaldarius esterase than to Archaeoglobus fulgidus enzyme suggesting, in turn, a less compact structure of the former enzyme. The fluorescence studies showed that the intrinsic tryptophanyl fluorescence of the Bacillus acidocaldarius protein was well represented by the three-exponential model, and that the temperature affected the protein conformational dynamics. The data suggested an increase in the protein flexibility on increasing the temperature. Moreover, comparison of Bacillus acidocaldarius esterase with the Archaeoglobus fugidus enzyme fluorescence data indicated a higher flexibility of the former enzyme at all temperatures tested, supporting the infrared data and giving a possible explanation of its unusual relative high activity at low temperatures. Proteins 2000;40:473-481.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0887-3585
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
473-81
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
The esterase from the thermophilic eubacterium Bacillus acidocaldarius: structural-functional relationship and comparison with the esterase from the hyperthermophilic archaeon Archaeoglobus fulgidus.
pubmed:affiliation
Center for Fluorescence Spectroscopy, University of Maryland, School of Medicine, Baltimore, Maryland 21201, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't