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Galactomannan catabolism conferred by a polysaccharide utilisation locus of Bacteroides ovatus : enzyme synergy and crystal structure of a β-mannanase

Bågenholm, Viktoria LU ; KRISHNASWAMYREDDY, SUMITHA LU ; Bouraoui, Hanene; Morrill, Johan LU ; Kulcinskaja, Evelina LU ; Bahr, Constance; AURELIUS, OSKAR LU ; Rogers, Theresa; Xiao, Yao and Logan, Derek LU , et al. (2017) In Journal of Biological Chemistry 292(1). p.229-243
Abstract (Swedish)
A recently identified polysaccharide utilisation locus (PUL) from Bacteroides ovatus ATCC8483 is transcriptionally upregulated during growth on galacto- and glucomannans. It encodes two putative glycoside hydrolase family 26 (GH26) β-mannanases, BoMan26A and BoMan26B, and a GH36 α-galactosidase, BoGal36A. The PUL also includes two glycan binding proteins, confirmed by β-mannan affinity electrophoresis. When this PUL was deleted, B. ovatus was no longer able to grow on locust bean galactomannan. BoMan26A primarily formed mannobiose from mannan polysaccharides. BoMan26B had higher activity on galactomannan with a high degree of galactosyl substitution and was shown to be endo-acting generating... (More)
A recently identified polysaccharide utilisation locus (PUL) from Bacteroides ovatus ATCC8483 is transcriptionally upregulated during growth on galacto- and glucomannans. It encodes two putative glycoside hydrolase family 26 (GH26) β-mannanases, BoMan26A and BoMan26B, and a GH36 α-galactosidase, BoGal36A. The PUL also includes two glycan binding proteins, confirmed by β-mannan affinity electrophoresis. When this PUL was deleted, B. ovatus was no longer able to grow on locust bean galactomannan. BoMan26A primarily formed mannobiose from mannan polysaccharides. BoMan26B had higher activity on galactomannan with a high degree of galactosyl substitution and was shown to be endo-acting generating a more diverse mixture of oligosaccharides including mannobiose. Of the two β-mannanases, only BoMan26B hydrolysed galactoglucomannan. A crystal structure of BoMan26A revealed a similar structure to the exo-mannobiohydrolase CjMan26C from Cellvibrio japonicus, with a conserved glycone region (-1 and -2 subsites) including a conserved loop closing the active site beyond subsite -2. Analysis of cellular location by immuno-labelling and fluorescence microscopy suggests that BoMan26B is surface exposed, associated with the outer membrane, while BoMan26A and BoGal36A are likely periplasmic. In light of the cellular location and the biochemical properties of the two characterised β-mannanases, we propose a scheme of sequential action by the GHs encoded by the β-mannan PUL and involved in the β-mannan utilisation pathway in B. ovatus. The outer membrane associated BoMan26B initially acts on the polysaccharide galactomannan, producing comparably large oligosaccharide fragments. Galactomanno-oligosaccharides are further processed in the periplasm: degalactosylated by BoGal36A and subsequently hydrolysed into mainly mannobiose by the β-mannanase BoMan26A. (Less)
Abstract
A recently identified polysaccharide utilization locus (PUL) from Bacteroides ovatus ATCC 8483 is transcriptionally up-regulated during growth on galacto- and glucomannans. It encodes two glycoside hydrolase family 26 (GH26) β-mannanases, BoMan26A and BoMan26B, and a GH36 α-galactosidase, BoGal36A. The PUL also includes two glycan-binding proteins, confirmed by β-mannan affinity electrophoresis. When this PUL was deleted, B. ovatus was no longer able to grow on locust bean galactomannan. BoMan26A primarily formed mannobiose from mannan polysaccharides. BoMan26B had higher activity on galactomannan with a high degree of galactosyl substitution and was shown to be endo-acting generating a more diverse mixture of oligosaccharides, including... (More)
A recently identified polysaccharide utilization locus (PUL) from Bacteroides ovatus ATCC 8483 is transcriptionally up-regulated during growth on galacto- and glucomannans. It encodes two glycoside hydrolase family 26 (GH26) β-mannanases, BoMan26A and BoMan26B, and a GH36 α-galactosidase, BoGal36A. The PUL also includes two glycan-binding proteins, confirmed by β-mannan affinity electrophoresis. When this PUL was deleted, B. ovatus was no longer able to grow on locust bean galactomannan. BoMan26A primarily formed mannobiose from mannan polysaccharides. BoMan26B had higher activity on galactomannan with a high degree of galactosyl substitution and was shown to be endo-acting generating a more diverse mixture of oligosaccharides, including mannobiose. Of the two β-mannanases, only BoMan26B hydrolyzed galactoglucomannan. A crystal structure of BoMan26A revealed a similar structure to the exo-mannobiohydrolase CjMan26C from Cellvibrio japonicus, with a conserved glycone region (-1 and -2 subsites), including a conserved loop closing the active site beyond subsite -2. Analysis of cellular location by immunolabeling and fluorescence microscopy suggests that BoMan26B is surface-exposed and associated with the outer membrane, although BoMan26A and BoGal36A are likely periplasmic. In light of the cellular location and the biochemical properties of the two characterized β-mannanases, we propose a schemeof sequential action by the glycoside hydrolasesencodedby the β-mannanPULandinvolved in the β-mannanutilization pathway in B. ovatus. The outer membrane-associated BoMan26B initially acts on the polysaccharide galactomannan, producing comparably large oligosaccharide fragments. Galactomanno-oligosaccharides are further processed in the periplasm, degalactosylated by BoGal36A, and subsequently hydrolyzed into mainly mannobiose by the β-mannanase BoMan26A. (Less)
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Galactomannan catabolism conferred by a polysaccharide utilisation locus of <i>Bacteroides ovatus</i> : enzyme synergy and crystal structure of a β-mannanase
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Contribution to journal
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published
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Journal of Biological Chemistry
volume
292
issue
1
pages
15 pages
publisher
ASBMB
external identifiers
  • scopus:85009281007
  • wos:000391578000020
ISSN
1083-351X
DOI
10.1074/jbc.M116.746438
language
English
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yes
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3cd990ff-96a2-419c-aef0-135f18168af9
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2017-01-25 13:58:40
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2018-05-06 04:30:07
@article{3cd990ff-96a2-419c-aef0-135f18168af9,
  abstract     = {A recently identified polysaccharide utilization locus (PUL) from Bacteroides ovatus ATCC 8483 is transcriptionally up-regulated during growth on galacto- and glucomannans. It encodes two glycoside hydrolase family 26 (GH26) β-mannanases, BoMan26A and BoMan26B, and a GH36 α-galactosidase, BoGal36A. The PUL also includes two glycan-binding proteins, confirmed by β-mannan affinity electrophoresis. When this PUL was deleted, B. ovatus was no longer able to grow on locust bean galactomannan. BoMan26A primarily formed mannobiose from mannan polysaccharides. BoMan26B had higher activity on galactomannan with a high degree of galactosyl substitution and was shown to be endo-acting generating a more diverse mixture of oligosaccharides, including mannobiose. Of the two β-mannanases, only BoMan26B hydrolyzed galactoglucomannan. A crystal structure of BoMan26A revealed a similar structure to the exo-mannobiohydrolase CjMan26C from Cellvibrio japonicus, with a conserved glycone region (-1 and -2 subsites), including a conserved loop closing the active site beyond subsite -2. Analysis of cellular location by immunolabeling and fluorescence microscopy suggests that BoMan26B is surface-exposed and associated with the outer membrane, although BoMan26A and BoGal36A are likely periplasmic. In light of the cellular location and the biochemical properties of the two characterized β-mannanases, we propose a schemeof sequential action by the glycoside hydrolasesencodedby the β-mannanPULandinvolved in the β-mannanutilization pathway in B. ovatus. The outer membrane-associated BoMan26B initially acts on the polysaccharide galactomannan, producing comparably large oligosaccharide fragments. Galactomanno-oligosaccharides are further processed in the periplasm, degalactosylated by BoGal36A, and subsequently hydrolyzed into mainly mannobiose by the β-mannanase BoMan26A.},
  author       = {Bågenholm, Viktoria and KRISHNASWAMYREDDY, SUMITHA and Bouraoui, Hanene and Morrill, Johan and Kulcinskaja, Evelina and Bahr, Constance and AURELIUS, OSKAR and Rogers, Theresa and Xiao, Yao and Logan, Derek and Martens, Eric and Koropatkin, Nicole M and Stålbrand, Henrik},
  issn         = {1083-351X},
  language     = {eng},
  month        = {01},
  number       = {1},
  pages        = {229--243},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Galactomannan catabolism conferred by a polysaccharide utilisation locus of <i>Bacteroides ovatus </i>: enzyme synergy and crystal structure of a β-mannanase},
  url          = {http://dx.doi.org/10.1074/jbc.M116.746438},
  volume       = {292},
  year         = {2017},
}