Computational modeling and functional characterization of a GgChi: A class III chitinase from corms of Gladiolus grandiflorus

Publication date: Available online 12 October 2018Source: The Kaohsiung Journal of Medical SciencesAuthor(s): Maria Rafiq, Ashiq Hussain, Kausar Hussain Shah, Qamar Saeed, Muhammad Umair Sial, Zahid Ali, Friedrich Buck, Richard E. Goodman, Binish Khaliq, Uzma Ishaq, Mirza Ahsen Baig, Aisha Munawar, Seema Mahmood, Ahmed AkremAbstractThe present study describes the predicted model and functional characterization of an endochitinase (30 kDa) from corms of Gladiolus grandiflorus. ESI-QTOF-MS generated peptide showed 96% sequence homology with family 18, Class III acidic endochitinase of Gladiolus gandavensis. Purified G. grandiflorus chitinase (GgChi) hydrolyzed 4-methylumbelliferyl β-d-N,N′,N′′-triacetylchitotriose substrate showing specific endochitinase activity. Since no structural details of GgChi were available in the Protein Data Bank (PDB), a homology model was predicted using the coordinate information of Crocus vernus chitinase (PDB ID: 3SIM). Ramachandran plot indicated 84.5% in most favored region, 14.8% in additional and 0.6% in generously allowed region while no residue in disallowed region. The predicted structure indicated a highly conserved (β/α)8 (TIM barrel) structure similar to the family 18, class III chitinases. The GgChi also showed sequence and structural homologies with other active chitinases. The GgChi (50 μg/disc) showed no antibacterial activity, but did provide mild growth inhibition of phytopathogenic fungus Fusarium oxysporum at a concen...
Source: The Kaohsiung Journal of Medical Sciences - Category: Universities & Medical Training Source Type: research