1rqm
From Proteopedia
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'''SOLUTION STRUCTURE OF THE K18G/R82E ALICYCLOBACILLUS ACIDOCALDARIUS THIOREDOXIN MUTANT''' | '''SOLUTION STRUCTURE OF THE K18G/R82E ALICYCLOBACILLUS ACIDOCALDARIUS THIOREDOXIN MUTANT''' | ||
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[[Category: Rossi, M.]] | [[Category: Rossi, M.]] | ||
[[Category: Saviano, M.]] | [[Category: Saviano, M.]] | ||
| - | [[Category: | + | [[Category: Redox-active center]] |
| - | [[Category: | + | [[Category: Thioredoxin fold]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 07:47:56 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 04:47, 3 May 2008
SOLUTION STRUCTURE OF THE K18G/R82E ALICYCLOBACILLUS ACIDOCALDARIUS THIOREDOXIN MUTANT
Overview
No general strategy for thermostability has been yet established, because the extra stability of thermophiles appears to be the sum of different cumulative stabilizing interactions. In addition, the increase of conformational rigidity observed in many thermophilic proteins, which in some cases disappears when mesophilic and thermophilic proteins are compared at their respective physiological temperatures, suggests that evolutionary adaptation tends to maintain corresponding states with respect to conformational flexibility. In this study, we accomplished a structural analysis of the K18G/R82E Alicyclobacillus acidocaldarius thioredoxin (BacTrx) mutant, which has reduced heat resistance with respect to the thermostable wild-type. Furthermore, we have also achieved a detailed study, carried out at 25, 45, and 65 degrees C, of the backbone dynamics of both the BacTrx and its K18G/R82E mutant. Our findings clearly indicate that the insertion of the two mutations causes a loss of energetically favorable long-range interactions and renders the secondary structure elements of the double mutants more similar to those of the mesophilic Escherichia coli thioredoxin. Moreover, protein dynamics analysis shows that at room temperature the BacTrx, as well as the double mutant, are globally as rigid as the mesophilic thioredoxins; differently, at 65 degrees C, which is in the optimal growth temperature range of A. acidocaldarius, the wild-type retains its rigidity while the double mutant is characterized by a large increase of the amplitude of the internal motions. Finally, our research interestingly shows that fast motions on the pico- to nanosecond time scale are not detrimental to protein stability and provide an entropic stabilization of the native state. This study further confirms that protein thermostability is reached through diverse stabilizing interactions, which have the key role to maintain the structural folding stable and functional at the working temperature.
About this Structure
1RQM is a Single protein structure of sequence from Alicyclobacillus acidocaldarius. Full crystallographic information is available from OCA.
Reference
Solution structure and backbone dynamics of the K18G/R82E Alicyclobacillus acidocaldarius thioredoxin mutant: a molecular analysis of its reduced thermal stability., Leone M, Di Lello P, Ohlenschlager O, Pedone EM, Bartolucci S, Rossi M, Di Blasio B, Pedone C, Saviano M, Isernia C, Fattorusso R, Biochemistry. 2004 May 25;43(20):6043-58. PMID:15147188 Page seeded by OCA on Sat May 3 07:47:56 2008
