Document Detail

Amino acid substitutions of His296 alter the catalytic properties of Zymomonas mobilis 10232 levansucrase.
MedLine Citation:
PMID:  18324341     Owner:  NLM     Status:  MEDLINE    
His296 of Zymomonas mobilis levansucrase (EC is crucial for the catalysis of the transfructosylation reaction. The three-dimensional structures of levansucrases revealed the His296 is involved in the substrate recognition and binding. In this study, nine mutants were created by site-directed mutagenesis, in which His296 was substituted with amino acids of different polarity, charge and length. The substitutions of His296 with Arg or Trp retained partial hydrolysis and transfructosylation activities. The positively charged Lys substitution resulted in a 2.5-fold increase of sucrose hydrolysis. Substitutions with short (Cys or Ser), negatively charged (Glu) or polar (Tyr) amino acids virtually abolished both the activities. Analysis of transfructosylation products indicated that the mutants synthesized different oligosaccharides, suggesting that amino acid substitutions of His296 strongly affected both the enzyme activity and transfructosylation products.
Shu Ying Li; Ming Chen; Gang Li; Yong Liang Yan; Hai Ying Yu; Yu Hua Zhan; Zi Xin Peng; Jin Wang; Min Lin
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-03-07
Journal Detail:
Title:  Acta biochimica Polonica     Volume:  55     ISSN:  0001-527X     ISO Abbreviation:  Acta Biochim. Pol.     Publication Date:  2008  
Date Detail:
Created Date:  2008-03-28     Completed Date:  2008-09-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  14520300R     Medline TA:  Acta Biochim Pol     Country:  Poland    
Other Details:
Languages:  eng     Pagination:  201-6     Citation Subset:  IM    
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, PR China.
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MeSH Terms
Amino Acid Substitution
Arginine / chemistry
Hexosyltransferases / chemistry*
Histidine / chemistry*
Models, Molecular
Mutagenesis, Site-Directed
Oligonucleotides / chemistry
Oligosaccharides / chemistry
Protein Conformation
Sucrose / chemistry
Tryptophan / chemistry
Zymomonas / enzymology*
Reg. No./Substance:
0/Oligonucleotides; 0/Oligosaccharides; 57-50-1/Sucrose; 71-00-1/Histidine; 73-22-3/Tryptophan; 74-79-3/Arginine; EC 2.4.1.-/Hexosyltransferases; EC

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