Medicinal & Aromatic Plants
Open Access
ISSN: 2167-0412
ISSN: 2167-0412
Ubaid Yaqoob, Tanushri Kaul and Irshad Ahmad Nawchoo
The Acetohydroxyacid synthase (EC 2.2.1.6) or Acetolactate synthase (ALS) belongs to a family of thiamine diphosphate (TPP) dependent enzymes which catalyzes the first reaction in the biosynthesis of essential amino acids - isoleucine, leucine and valine. Acetohydroxyacid synthase (AHAS) is present in plants, algae, fungi and bacteria and is found to be a vital target of multiple herbicides. We revealed the homology model of OsAHAS protein using the structure of Arabidopsis thaliana AHAS (PDB ID: 3E9Y) as template. The resulting model structure was refined by PROCHECK, ProSA, RMSD and Verify3D that indicated the model structure is reliable with 76% amino acid sequence identity with template. RMSD (1.75Å), Verify3D (86.02%), Z-score (-9.55) and Ramachandran plot analysis showed that conformations for 81.6% of amino acid residues are within the most favoured regions. The phylogenetic tree constructed revealed different clusters based on AHAS in respect of bacteria, fungi, algae and plants. The multiple sequence alignment of these AHAS protein sequences from different organisms showed conserved regions at different stretches with homology in amino acid residues. Through motif analysis, it was revealed that conserved AHAS domain are found in all AHAS proteins suggesting its possible role in cellular and metabolic functions.