In silico analysis of
P5CS gene evolution in plants.
Kumari A1, Patade VY, Suprasanna P.
Plant Cell Culture Technology Section, Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Centre, Trombay,
Mumbai 400 084.
ABSTRACT
Kumari A, Patade VY, Suprasanna P., In Silico analysis
of P5CS gene evolution in plants, Onl J Bioinform., 9 (1): 1-11, 2008. Proline is a ubiquitous osmoprotectant and plants synthesize proline mainly through
glutamate pathway under abiotic stress. The bifunctional enzyme, P5CS catalyses the first and rate limiting step in proline
biosynthesis. In this study, the molecular evolution of the P5CS gene of
higher plants was investigated. The PUA domain was found to be completely
removed during evolution, so as to increase the efficiency of the bifunctional
P5CS enzyme. Comparative analysis of the domain architectures combined with
sequence-based phylogenetic analysis of the γ Glutamyl
kinase and L Glutamate γ- semialdehyde
dehydrogenase of the enzyme revealed conservation of the domains, from bacteria
to plants, with minor variations. The β4-αE loop of G5K is found to
be conserved throught the plants, which play an
important role in feedback inhibition. Codon substitution analysis revealed
0.508 as ratio of non-synonymous to synonymous substitution (ω) for the
entire coding region, suggesting the purifying selection of the gene sequence
in nature. However, for few coding sites ω values were significantly
higher indicating the presence of buffer sites for mutations in coding
sequence.
Keywords: proline, P5CS, GK, GSA
dehydrogenase, molecular evolution, Ka/Ks Abbreviations: CDS-Coding Sequence;
P5CS- delta1-pyrolline-5-carboxylate synthetase;
ENC-Effective Number of Codons; G5K- γ Glutamyl
kinase; GSA- L Glutamate γ- semialdehyde; PUA- Pseudouridine synthases. Authors contribution was equal
FULL-TEXT
(SUBSCRIPTION OR PURCHASE TITLE $25USD)