Linked Life Data

12364584

Source:http://linkedlifedata.com/resource/pubmed/id/12364584

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2002-10-4
pubmed:abstractText
N-Carbamyl-D-amino acid amidohydrolase (N-carbamoylase), which is currently employed in the industrial production of unnatural D-amino acid in conjunction with D-hydantoinase, has low oxidative and thermostability. We attempted the simultaneous improvement of the oxidative and thermostability of N-carbamoylase from Agrobacterium tumefaciens NRRL B11291 by directed evolution using DNA shuffling. In a second generation of evolution, the best mutant 2S3 with improved oxidative and thermostability was selected, purified and characterized. The temperature at which 50% of the initial activity remains after incubation for 30 min was 73 degrees C for 2S3, whereas it was 61 degrees C for wild-type enzyme. Treatment of wild-type enzyme with 0.2 mM hydrogen peroxide for 30 min at 25 degrees C resulted in a complete loss of activity, but 2S3 retained about 79% of the initial activity under the same conditions. The K(m) value of 2S3 was estimated to be similar to that of wild-type enzyme; however k(cat) was decreased, leading to a slightly reduced value of k(cat)/K(m), compared with wild-type enzyme. DNA sequence analysis revealed that six amino acid residues were changed in 2S3 and substitutions included Q23L, V40A, H58Y, G75S, M184L and T262A. The stabilizing effects of each amino acid residue were investigated by incorporating mutations individually into wild-type enzyme. Q23L, H58Y, M184L and T262A were found to enhance both oxidative and thermostability of the enzyme and of them, T262A showed the most significant effect. V40A and G75S gave rise to an increase only in oxidative stability. The positions of the mutated amino acid residues were identified in the structure of N-carbamoylase from Agrobacterium sp. KNK 712 and structural analysis of the stabilizing effects of each amino acid substitution was also carried out.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0269-2139
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
689-95
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Improvement of oxidative and thermostability of N-carbamyl-d-amino Acid amidohydrolase by directed evolution.
pubmed:affiliation
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 373-1, Kusung-dong, Yusung-Gu, Taejon, 305-701, South Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't