Structure of Bacillus amyloliquefaciens alpha-amylase at high resolution: implications for thermal stability.
The crystal structure of Bacillus amyloliquefaciens alpha-amylase (BAA) at 1.4 A resolution revealed ambiguities in the thermal adaptation of homologous proteins in this family. The final model of BAA is composed of two molecules in a back-to-back orientation, which is likely to be a consequence of crystal packing. Despite a high degree of identity, comparison of the structure of BAA with those of other liquefying-type alpha-amylases indicated moderate discrepancies at the secondary-structural level. Moreover, a domain-displacement survey using anisotropic B-factor and domain-motion analyses implied a significant contribution of domain B to the total flexibility of BAA, while visual inspection of the structure superimposed with that of B. licheniformis alpha-amylase (BLA) indicated higher flexibility of the latter in the central domain A. Therefore, it is suggested that domain B may play an important role in liquefying alpha-amylases, as its rigidity offers a substantial improvement in thermostability in BLA compared with BAA.
Alikhajeh
Jahan
J
Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan. khajeh@modares.ac.ir
Khajeh
Khosro
K
Ranjbar
Bijan
B
Naderi-Manesh
Hossein
H
Lin
Yi Hung
YH
Liu
Enhung
E
Guan
Hong Hsiang
HH
Hsieh
Yin Cheng
YC
Chuankhayan
Phimonphan
P
Huang
Yen Chieh
YC
Jeyaraman
Jeyakanthan
J
Liu
Ming Yih
MY
Chen
Chun Jung
CJ
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D055672:Static Electricity; D040681:Structural Homology, Protein; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism
D000516:alpha-Amylases