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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.49 [2011] >
IJEB Vol.49(12) [December 2011] >
| Title: | Construction and functional characterization of double and triple mutants of parallel  -bulge of ubiquitin |
| Authors: | Sharma, Mrinal
Prabha, C Ratna |
| Keywords: | -Bulge
Cancer
Ubiquitin
Ubiquitin proteasome system (UPS)
Virus |
| Issue Date: | Dec-2011 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Ubiquitin,
a small eukaryotic protein serving as a post-translational modification on many
important proteins, plays central role in cellular homeostasis and cell cycle
regulation. Ubiquitin features two -bulges, the second -bulge, located at the
C-terminal region of the protein along with type II turn, holds 3 residues
Glu64(1), Ser65(2) and Gln2(X). Percent frequency of occurrence of such a
sequence in parallel -bulge is very low. However, the sequence and structure
have been conserved in ubiquitin through out the evolution. Present study
involves replacement of residues in unusual -bulge of ubiquitin by introducing
mutations in combination through site directed mutagenesis, generating double
and triple mutants and their functional characterization. Mutant ubiquitins
cloned in yeast expression vector YEp96 tested for growth profile, viability
assay and heat stress complementation study have revealed significant decrease
in growth rate, loss of viability and non-complementation of heat sensitive
phenotype with UbE64G-S65D and UbQ2N-E64G-S65D mutations. However, UbQ2N-S65D
did not show any negative effects in the above assays. Present results show
that, replacement of residues in
-bulge of ubiquitin exerts severe effects on growth and viability in Saccharomyces cerevisiae due to
functional failure of the mutant ubiquitins UbE64G-S65D and UbQ2N-E64G-S65D. |
| Page(s): | 919-924 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.49(12) [December 2011]
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