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Deciphering ligand specificity of a Clostridium thermocellum family 35 carbohydrate binding module (CtCBM35) for Gluco- and Galacto- Substituted mannans and Its calcium induced stability

2013-12-06Journal article Open access
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dc.contributor.authorGhosh, Arabinda
dc.contributor.authorLuís, Ana Sofia
dc.contributor.authorBrás, Joana L. A.
dc.contributor.authorPathaw, Neeta
dc.contributor.authorChrungoo, Nikhil K.
dc.contributor.authorFontes, Carlos M. G. A.
dc.contributor.authorGoyal, Arun
dc.date.accessioned2014-09-25T15:32:57Z
dc.date.available2014-09-25T15:32:57Z
dc.date.issued2013-12-06
dc.descriptionArticles in International Journalspor
dc.description.abstractThis study investigated the role of CBM35 from Clostridium thermocellum (CtCBM35) in polysaccharide recognition. CtCBM35 was cloned into pET28a (+) vector with an engineered His6 tag and expressed in Escherichia coli BL21 (DE3) cells. A homogenous 15 kDa protein was purified by immobilized metal ion chromatography (IMAC). Ligand binding analysis of CtCBM35 was carried out by affinity electrophoresis using various soluble ligands. CtCBM35 showed a manno-configured ligand specific binding displaying significant association with konjac glucomannan (Ka = 14.3×104 M−1), carob galactomannan (Ka = 12.4×104 M−1) and negligible association (Ka = 12 µM−1) with insoluble mannan. Binding of CtCBM35 with polysaccharides which was calcium dependent exhibited two fold higher association in presence of 10 mM Ca2+ ion with konjac glucomannan (Ka = 41×104 M−1) and carob galactomannan (Ka = 30×104 M−1). The polysaccharide binding was further investigated by fluorescence spectrophotometric studies. On binding with carob galactomannan and konjac glucomannan the conformation of CtCBM35 changed significantly with regular 21 nm peak shifts towards lower quantum yield. The degree of association (Ka) with konjac glucomannan and carob galactomannan, 14.3×104 M−1 and 11.4×104 M−1, respectively, corroborated the findings from affinity electrophoresis. The association of CtCBM35with konjac glucomannan led to higher free energy of binding (ΔG) −25 kJ mole−1 as compared to carob galactomannan (ΔG) −22 kJ mole−1. On binding CtCBM35 with konjac glucomannan and carob galactomannan the hydrodynamic radius (RH) as analysed by dynamic light scattering (DLS) study, increased to 8 nm and 6 nm, respectively, from 4.25 nm in absence of ligand. The presence of 10 mM Ca2+ ions imparted stiffer orientation of CtCBM35 particles with increased RH of 4.52 nm. Due to such stiffer orientation CtCBM35 became more thermostable and its melting temperature was shifted to 70°C from initial 50°C.por
dc.identifier.citationGhosh, A., et al. (2013). Deciphering ligand specificity of a Clostridium thermocellum family 35 carbohydrate binding module (CtCBM35) for Gluco- and Galacto- Substituted mannans and Its calcium induced stability. PLoS ONE, 8(12): e80415, 1-11. doi: 10.1371/ journal.pone.0080415por
dc.identifier.doi10.1371/journal.pone.0080415
dc.identifier.issn1932-6203 (online)
dc.identifier.urihttp://hdl.handle.net/10400.5/7208
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherMichael Massiah, George Washington University, United States of Americapor
dc.subjectAdsorptionpor
dc.subjectBinding analysispor
dc.subjectCarbohydratespor
dc.subjectClostridiumpor
dc.subjectFluorescencepor
dc.subjectHydrodynamicspor
dc.subjectMeltingpor
dc.subjectPolysaccharidespor
dc.titleDeciphering ligand specificity of a Clostridium thermocellum family 35 carbohydrate binding module (CtCBM35) for Gluco- and Galacto- Substituted mannans and Its calcium induced stabilitypor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage11por
oaire.citation.startPage1por
oaire.citation.titlePLoS ONEpor
oaire.citation.volumeVol. 8(12),e80415por
rcaap.rightsopenAccesspor
rcaap.typearticlepor

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