Computational modeling and functional characterization of a GgChi

TY - JOUR

T1 - Computational modeling and functional characterization of a GgChi

T2 - A class III chitinase from corms of Gladiolus grandiflorus

AU - Rafiq, Maria

AU - Hussain, Ashiq

AU - Shah, Kausar Hussain

AU - Saeed, Qamar

AU - Sial, Muhammad Umair

AU - Ali, Zahid

AU - Buck, Friedrich

AU - Goodman, Richard E

AU - Khaliq, Binish

AU - Ishaq, Uzma

AU - Baig, Mirza Ahsen

AU - Munawar, Aisha

AU - Mahmood, Seema

AU - Akrem, Ahmed

N1 - Copyright © 2018. Published by Elsevier Taiwan LLC.

PY - 2018/12

Y1 - 2018/12

N2 - The 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 concentration of 500 μg/well Similarly, insect toxicity bioassays of GgChi (50 μg) against nymphs of Bemisia tabaci showed 14% reduction in adult emergence and 14% increase in mortality rate in comparison to control values. The GgChi (1.5 mg) protein showed significant reduction in a population of flour beetle (Tribolium castaneum) after 35 days, but lower reactivity against rice weevil (Sitophilus oryzae). The results of this study provide detai.led insight on functional characterization of a family 18 class III acidic plant endochitinase.

AB - The 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 concentration of 500 μg/well Similarly, insect toxicity bioassays of GgChi (50 μg) against nymphs of Bemisia tabaci showed 14% reduction in adult emergence and 14% increase in mortality rate in comparison to control values. The GgChi (1.5 mg) protein showed significant reduction in a population of flour beetle (Tribolium castaneum) after 35 days, but lower reactivity against rice weevil (Sitophilus oryzae). The results of this study provide detai.led insight on functional characterization of a family 18 class III acidic plant endochitinase.

KW - Amino Acid Sequence

KW - Animals

KW - Anti-Bacterial Agents/pharmacology

KW - Antifungal Agents/pharmacology

KW - Bacteria/drug effects

KW - Chitinases/chemistry

KW - Databases, Protein

KW - Enzyme Assays

KW - Fungi/drug effects

KW - Hemiptera/drug effects

KW - Insecticides/toxicity

KW - Iridaceae/enzymology

KW - Microbial Sensitivity Tests

KW - Models, Molecular

KW - Plant Proteins/chemistry

KW - Spectrometry, Mass, Electrospray Ionization

KW - Structural Homology, Protein

U2 - 10.1016/j.kjms.2018.08.003

DO - 10.1016/j.kjms.2018.08.003

M3 - SCORING: Journal article

C2 - 30527201

VL - 34

SP - 673

EP - 683

JO - KAOHSIUNG J MED SCI

JF - KAOHSIUNG J MED SCI

SN - 1607-551X

IS - 12

ER -