Carbohydrate-binding modules from a thermostable Rhodothermus marinus xylanase : Cloning, expression and binding studies

Abou Hachem, MaherLund University,Lunds universitet,Bioteknik,Centrum för tillämpade biovetenskaper,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biotechnology,Center for Applied Life Sciences,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH (author)

The two N-terminally repeated carbohydrate-binding modules (CBM4-1 and CBM4-2) encoded by xyn10A from Rhodothermus marinus were produced in Escherichia coli and purified by affinity chromatography. Binding assays to insoluble polysaccharides showed binding to insoluble xylan and to phosphoric-acid-swollen cellulose but not to Avicel or crystalline cellulose. Binding to insoluble substrates was significantly enhanced by the presence of Na+ and Ca2+ ions. The binding affinities for soluble polysaccharides were tested by affinity electrophoresis; strong binding occurred with different xylans and β-glucan. CBM4-2 displayed a somewhat higher binding affinity than CBM4-1 for both soluble and insoluble substrates but both had similar specificities. Binding to short oligosaccharides was measured by NMR; both modules bound with similar affinities. The binding of the modules was shown to be dominated by enthalpic forces. The binding modules did not contribute with any significant synergistic effects on xylan hydrolysis when incubated with a Xyn10A catalytic module. This is the first report of family 4 CBMs with affinity for both insoluble xylan and amorphous cellulose.

Nordberg Karlsson, EvaLund University,Lunds universitet,Bioteknik,Centrum för tillämpade biovetenskaper,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biotechnology,Center for Applied Life Sciences,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)biot-eno (author)
Bartonek-Roxå, EvaLund University,Lunds universitet,Bioteknik,Centrum för tillämpade biovetenskaper,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biotechnology,Center for Applied Life Sciences,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)med-ebx (author)
Raghothama, SrinivasraoUniversity of Sheffield (author)
Simpson, Peter J.University of Sheffield (author)
Gilbert, Harry J.University of Newcastle upon Tyne (author)
Williamson, Michael P.University of Sheffield (author)
Holst, OlleLund University,Lunds universitet,Bioteknik,Centrum för tillämpade biovetenskaper,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biotechnology,Center for Applied Life Sciences,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)biot-oho (author)
BioteknikCentrum för tillämpade biovetenskaper (creator_code:org_t)

By the author/editor: Abou Hachem, Mah ...; Nordberg Karlsso ...; Bartonek-Roxå, E ...; Raghothama, Srin ...; Simpson, Peter J ...; Gilbert, Harry J ...; show more...; Williamson, Mich ...; Holst, Olle; show less...

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Biological Scien ...; and Biochemistry and ...

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