3BCF

Alpha-amylase B from Halothermothrix orenii


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal Structure of the Polyextremophilic alpha-Amylase AmyB from Halothermothrix orenii: Details of a Productive Enzyme-Substrate Complex and an N Domain with a Role in Binding Raw Starch

Tan, T.-C.Mijts, B.N.Swaminathan, K.Patel, B.K.C.Divne, C.

(2008) J.Mol.Biol. 378: 850-868

  • DOI: 10.1016/j.jmb.2008.02.041
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The gene for a membrane-bound, halophilic, and thermostable alpha-amylase, AmyB, from Halothermothrix orenii was cloned and sequenced. The crystal structure shows that, in addition to the typical domain organization of family 13 glycoside hydrolases, ...

    The gene for a membrane-bound, halophilic, and thermostable alpha-amylase, AmyB, from Halothermothrix orenii was cloned and sequenced. The crystal structure shows that, in addition to the typical domain organization of family 13 glycoside hydrolases, AmyB carries an additional N-terminal domain (N domain) that forms a large groove--the N-C groove--some 30 A away from the active site. The structure of AmyB with the inhibitor acarbose at 1.35 A resolution shows that a nonasaccharide has been synthesized through successive transglycosylation reactions of acarbose. Unexpectedly, in a complex of wild-type AmyB with alpha-cyclodextrin and maltoheptaose at 2.2 A resolution, a maltotetraose molecule is bound in subsites -1 to +3, spanning the cleavage point at -1/+1, with the -1 glucosyl residue present as a (2)S(o) skew boat. This wild-type AmyB complex was obtained in the presence of a large excess of substrate, a condition under which it is possible to capture Michaelis complexes, which may explain the observed binding across -1/+1 and ring distortion. We observe three methionine side chains that serve as "binding platforms" for glucosyl rings in AmyB, a seemingly rare occurrence in carbohydrate-binding proteins. The structures and results from the biochemical characterization of AmyB and AmyB lacking the N domain show that the N domain increases binding of the enzyme to raw starch. Furthermore, theoretical modeling suggests that the N-C groove can accommodate, spatially and chemically, large substrates such as A-starch.


    Organizational Affiliation

    KTH School of Biotechnology, AlbaNova University Center, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Alpha amylase, catalytic region
A
599Halothermothrix orenii (strain H 168 / OCM 544 / DSM 9562)Mutation(s): 0 
EC: 3.2.1.98
Find proteins for B8CZ54 (Halothermothrix orenii (strain H 168 / OCM 544 / DSM 9562))
Go to UniProtKB:  B8CZ54
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.191 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 226.620α = 90.00
b = 77.820β = 99.38
c = 50.330γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data scaling
MOLREPphasing
HKL-2000data collection
HKL-2000data reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-04-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Refinement description, Source and taxonomy, Version format compliance