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PDBsum entry 5agd
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PDB id:
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Hydrolase
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Title:
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An inactive (d125n) variant of the catalytic domain, bcgh76, of bacillus circulans aman6 in complex with alpha-1,6-mannopentaose
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Structure:
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Alpha-1,6-mannanase. Chain: a, b. Fragment: catalytic domain, unp residues 35-375. Engineered: yes. Mutation: yes
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Source:
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Bacillus circulans. Organism_taxid: 1397. Strain: tn31. Atcc: 29101. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Expression_system_variant: tuner.
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Resolution:
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1.20Å
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R-factor:
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0.122
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R-free:
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0.144
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Authors:
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A.J.Thompson,G.Speciale,J.Iglesias-Fernandez,Z.Hakki,T.Belz, A.Cartmell,R.J.Spears,E.Chandler,M.J.Temple,J.Stepper,H.J.Gilbert, C.Rovira,S.J.Williams,G.J.Davies
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Key ref:
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A.J.Thompson
et al.
(2015).
Evidence for a boat conformation at the transition state of GH76 α-1,6-mannanases--key enzymes in bacterial and fungal mannoprotein metabolism.
Angew Chem Int Ed Engl,
54,
5378-5382.
PubMed id:
DOI:
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Date:
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29-Jan-15
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Release date:
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25-Mar-15
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PROCHECK
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Headers
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References
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Q9Z4P9
(Q9Z4P9_NIACI) -
Alpha-1,6-mannanase from Niallia circulans
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Seq:
Struc:
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589 a.a.
333 a.a.*
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Key: |
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PfamA domain |
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Secondary structure |
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CATH domain |
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*
PDB and UniProt seqs differ
at 2 residue positions (black
crosses)
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Enzyme class:
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E.C.3.2.1.101
- mannan endo-1,6-alpha-mannosidase.
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Reaction:
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Random hydrolysis of 1,6-beta-D-mannosidic linkages in unbranched 1,6-mannans.
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DOI no:
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Angew Chem Int Ed Engl
54:5378-5382
(2015)
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PubMed id:
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Evidence for a boat conformation at the transition state of GH76 α-1,6-mannanases--key enzymes in bacterial and fungal mannoprotein metabolism.
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A.J.Thompson,
G.Speciale,
J.Iglesias-Fernández,
Z.Hakki,
T.Belz,
A.Cartmell,
R.J.Spears,
E.Chandler,
M.J.Temple,
J.Stepper,
H.J.Gilbert,
C.Rovira,
S.J.Williams,
G.J.Davies.
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ABSTRACT
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α-Mannosidases and α-mannanases have attracted attention for the insight they
provide into nucleophilic substitution at the hindered anomeric center of
α-mannosides, and the potential of mannosidase inhibitors as cellular probes
and therapeutic agents. We report the conformational itinerary of the family
GH76 α-mannanases studied through structural analysis of the Michaelis complex
and synthesis and evaluation of novel aza/imino sugar inhibitors. A Michaelis
complex in an (O) S2 conformation, coupled with distortion of an azasugar in an
inhibitor complex to a high energy B2,5 conformation are rationalized through
ab initio QM/MM metadynamics that show how the enzyme surface restricts the
conformational landscape of the substrate, rendering the B2,5 conformation the
most energetically stable on-enzyme. We conclude that GH76 enzymes perform
catalysis using an itinerary that passes through (O) S2 and B2,5 (≠)
conformations, information that should inspire the development of new antifungal
agents.
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