Activity and stability of a thermostable alpha-amylase compared to its mesophilic homologue: mechanisms of thermal adaptation.


Abstract

To elucidate how enzymes adapt to extreme environmental conditions, a comparative study with a thermostable alpha-amylase from Bacillus licheniformis (BLA) and its mesophilic homologue from Bacillus amyloliquefaciens (BAA) was performed. We measured conformational stability, catalytic activity, and conformational fluctuations on the picosecond time scale for both enzymes as a function of temperature. The objective of this study is to analyze how these properties are related to each other. BLA shows its maximal catalytic activity at about 90-95 degrees C and a strongly reduced activity (only 20% of the maximum) at room temperature. Although B. licheniformis itself is a mesophilic organism, BLA shows an activity profile typical for a thermophilic enzyme. In contrast to this, BAA exhibits its maximal activity at about 80 degrees C but with a level of about 60% activity at room temperature. In both cases the unfolding temperatures T(m) are only 6 degrees C (BAA, T(m) = 86 degrees C) and 10 degrees C (BLA, T(m) = 103 degrees C), respectively, higher than the temperatures for maximal activity. In contrast to many previous studies on other thermophilic-mesophilic pairs, in this study a higher structural flexibility of the thermostable BLA was measured as compared to the mesophilic BAA. The findings of this study neither indicate a proportionality between the observed dynamics and the catalytic activity nor support the idea of more "rigid" thermostable proteins, as often proposed in the concept of "corresponding states". Study holds ProTherm entries: 11670, 11671, 11672, 11673, 11674, 11675 Extra Details: additive : EDTA(20 mM), catalytic activity; thermophilic; mesophilic; structural flexibility

Submission Details

ID: 32pukbNp

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:42 p.m.

Version: 1

Publication Details
Fitter J;Herrmann R;Dencher NA;Blume A;Hauss T,Biochemistry (2001) Activity and stability of a thermostable alpha-amylase compared to its mesophilic homologue: mechanisms of thermal adaptation. PMID:11524019
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P
 

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)


Relevant PDB Entries

Structure ID Release Date Resolution Structure Title
3BH4 2008-12-09 1.4 High resolution crystal structure of Bacillus amyloliquefaciens alpha-amylase
1VJS 1997-03-12 1.7 STRUCTURE OF ALPHA-AMYLASE PRECURSOR
1E43 2001-06-21 1.7 Native structure of chimaeric amylase from B. amyloliquefaciens and B. licheniformis at 1.7A
1OB0 2003-01-30 1.83 Kinetic stabilization of Bacillus licheniformis alpha-amylase through introduction of hydrophobic residues at the surface
1E3X 2001-06-21 1.9 Native structure of chimaeric amylase from B. amyloliquefaciens and B. licheniformis at 1.92A
1BLI 1999-03-23 1.9 BACILLUS LICHENIFORMIS ALPHA-AMYLASE
1E3Z 2001-06-21 1.93 Acarbose complex of chimaeric amylase from B. amyloliquefaciens and B. licheniformis at 1.93A
1BPL 1996-08-17 2.2 GLYCOSYLTRANSFERASE
1E40 2001-06-21 2.2 Tris/maltotriose complex of chimaeric amylase from B. amyloliquefaciens and B. licheniformis at 2.2A

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
197.4 A,B GLYCOSYLTRANSFERASE P06278 AMY_BACLI
100.0 Alpha-amylase P00692 AMY_BACAM