title: Monomeric banana lectin at acidic pH overrules conformational stability of its native dimeric form.
abstract: Banana lectin (BL) is a homodimeric protein categorized among jacalin-related family of lectins. The effect of acidic pH was examined on conformational stability of BL by using circular dichroism, intrinsic fluorescence, 1-anilino-8-napthalene sulfonate (ANS) binding, size exclusion chromatography (SEC) and dynamic light scattering (DLS). During acid denaturation of BL, the monomerization of native dimeric protein was found at pH 2.0. The elution profile from SEC showed two different peaks (59.65 ml & 87.98 ml) at pH 2.0 while single peak (61.45 ml) at pH 7.4. The hydrodynamic radii (R h) of native BL was 2.9 nm while at pH 2.0 two species were found with R h of 1.7 and 3.7 nm. Furthermore at, pH 2.0 the secondary structures of BL remained unaltered while tertiary structure was significantly disrupted with the exposure of hydrophobic clusters confirming the existence of molten globule like state. The unfolding of BL with different subunit status was further evaluated by urea and temperature mediated denaturation to check their stability. As inferred from high Cm and ΔG values, the monomeric form of BL offers more resistance towards chemical denaturation than the native dimeric form. Besides, dimeric BL exhibited a Tm of 77°C while no loss in secondary structures was observed in monomers even up to 95°C. To the best of our knowledge, this is the first report on monomeric subunit of lectins showing more stability against denaturants than its native dimeric state.
authors: Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India.
authors: Javed M
authors: JM
authors: Khan
authors: Atiyatul
authors: A
authors: Qadeer
authors: Ejaz
authors: E
authors: Ahmad
authors: Raghib
authors: R
authors: Ashraf
authors: Bharat
authors: B
authors: Bhushan
authors: Sumit K
authors: SK
authors: Chaturvedi
authors: Gulam
authors: G
authors: Rabbani
authors: Rizwan H
authors: RH
authors: Khan
mesh_terms: D000143:Acids / Q000494:pharmacology*; D020106:Acrylamide / Q000378:metabolism; D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D002850:Chromatography, Gel; D002942:Circular Dichroism; D057446:Hydrodynamics; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D037102:Lectins / Q000737:chemistry* / Q000378:metabolism*; D008027:Light; D028521:Musa / Q000737:chemistry*; D011485:Protein Binding / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D055503:Protein Multimerization; D055550:Protein Stability / Q000187:drug effects; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D058767:Protein Unfolding / Q000187:drug effects; D012542:Scattering, Radiation; D012984:Software; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014364:Tryptophan / Q000378:metabolism; D014508:Urea / Q000494:pharmacology
chemical_list: D000143:Acids; D000817:Anilino Naphthalenesulfonates; D037102:Lectins; D020106:Acrylamide; C027132:1-anilino-8-naphthalenesulfonate; D014364:Tryptophan; D014508:Urea
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