A thermodynamic comparison of mesophilic and thermophilic ribonucleases H.


Abstract

The mechanisms by which thermophilic proteins attain their increased thermostability remain unclear, as usually the sequence and structure of these proteins are very similar to those of their mesophilic homologues. To gain insight into the basis of thermostability, we have determined protein stability curves describing the temperature dependence of the free energy of unfolding for two ribonucleases H, one from the mesophile Escherichia coli and one from the thermophile Thermus thermophilus. The circular dichroism signal was monitored as a function of temperature and guanidinium chloride concentration, and the resulting free energies of unfolding were fit to the Gibbs-Helmholtz equation to obtain a set of thermodynamic parameters for these proteins. Although the maximal stabilities for these proteins occur at similar temperatures, the heat capacity of unfolding for T. thermophilus RNase H is lower, resulting in a smaller temperature dependence of the free energy of unfolding and therefore a higher thermal melting temperature. In addition, the stabilities of these proteins are similar at the optimal growth temperatures for their respective organisms, suggesting that a balance of thermodynamic stability and flexibility is important for function. Study holds ProTherm entries: 5411, 5412 Extra Details:

Submission Details

ID: oMnHRDmi

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:30 p.m.

Version: 1

Publication Details
Hollien J;Marqusee S,Biochemistry (1999) A thermodynamic comparison of mesophilic and thermophilic ribonucleases H. PMID:10090773
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
4Z0U 2015-03-26T00:00:00+0000 2.0 RNase HI/SSB-Ct complex
1RIL 1993-01-14T00:00:00+0000 2.8 CRYSTAL STRUCTURE OF RIBONUCLEASE H FROM THERMUS THERMOPHILUS HB8 REFINED AT 2.8 ANGSTROMS RESOLUTION
2RPI 2008-05-16T00:00:00+0000 0 The NMR structure of the submillisecond folding intermediate of the Thermus thermophilus ribonuclease H
1JL2 2001-07-13T00:00:00+0000 1.76 Crystal structure of TCEO RNase H-a chimera combining the folding core from T. thermophilus RNase H and the remaining region of E. coli RNase H
1F21 2000-05-22T00:00:00+0000 1.4 DIVALENT METAL COFACTOR BINDING IN THE KINETIC FOLDING TRAJECTORY OF E. COLI RIBONUCLEASE HI
1G15 2000-10-10T00:00:00+0000 1.9 CO-CRYSTAL OF E. COLI RNASE HI WITH TWO MN2+ IONS BOUND IN THE THE ACTIVE SITE
1GOA 1993-05-10T00:00:00+0000 1.9 COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION
1GOB 1993-05-10T00:00:00+0000 2.0 COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION
1GOC 1993-05-10T00:00:00+0000 2.0 COOPERATIVE STABILIZATION OF ESCHERICHIA COLI RIBONUCLEASE HI BY INSERTION OF GLY-80B AND GLY-77-> ALA SUBSTITUTION
1JL1 2001-07-13T00:00:00+0000 1.3 D10A E. coli ribonuclease HI

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
98.8 Ribonuclease H Q72IE1 RNH_THET2
100.0 Ribonuclease H P29253 RNH_THET8
90.9 Ribonuclease HI A6T512 RNH_KLEP7
90.9 Ribonuclease HI B5Y1G2 RNH_KLEP3
92.9 Ribonuclease HI C0Q6N2 RNH_SALPC
93.5 Ribonuclease HI P0A2B9 RNH_SALTY
93.5 Ribonuclease HI P0A2C0 RNH_SALTI
93.5 Ribonuclease HI B4TYH0 RNH_SALSV
93.5 Ribonuclease HI B5BDW5 RNH_SALPK
93.5 Ribonuclease HI A9MZ19 RNH_SALPB
93.5 Ribonuclease HI Q5PFD8 RNH_SALPA
93.5 Ribonuclease HI B4SV39 RNH_SALNS
93.5 Ribonuclease HI B4TK85 RNH_SALHS
93.5 Ribonuclease HI B5R5L3 RNH_SALG2
93.5 Ribonuclease HI B5R449 RNH_SALEP
93.5 Ribonuclease HI B5FJ58 RNH_SALDC
93.5 Ribonuclease HI Q57SZ6 RNH_SALCH
93.5 Ribonuclease HI A9MPF1 RNH_SALAR
93.5 Ribonuclease HI B5F8X2 RNH_SALA4
93.5 Ribonuclease HI A8AKR0 RNH_CITK8
99.4 Ribonuclease HI Q0TLC3 RNH_ECOL5
99.4 Ribonuclease HI A7ZWF6 RNH_ECOHS
99.4 Ribonuclease HI B7LHC0 RNH_ECO55
99.4 Ribonuclease HI B7UJB0 RNH_ECO27
100.0 Ribonuclease HI Q3Z5E9 RNH_SHISS
100.0 Ribonuclease HI P0A7Y7 RNH_SHIFL
100.0 Ribonuclease HI Q32JP9 RNH_SHIDS
100.0 Ribonuclease HI Q325T2 RNH_SHIBS
100.0 Ribonuclease HI B2U352 RNH_SHIB3
100.0 Ribonuclease HI B7LW89 RNH_ESCF3
100.0 Ribonuclease HI B1LHM3 RNH_ECOSM
100.0 Ribonuclease HI B6HZS7 RNH_ECOSE
100.0 Ribonuclease HI B7N876 RNH_ECOLU
100.0 Ribonuclease HI P0A7Y4 RNH_ECOLI
100.0 Ribonuclease HI B1IPU4 RNH_ECOLC
100.0 Ribonuclease HI P0A7Y5 RNH_ECOL6
100.0 Ribonuclease HI B1XD78 RNH_ECODH
100.0 Ribonuclease HI C4ZRV1 RNH_ECOBW
100.0 Ribonuclease HI B7M213 RNH_ECO8A
100.0 Ribonuclease HI B7MQ23 RNH_ECO81
100.0 Ribonuclease HI B7NKW4 RNH_ECO7I
100.0 Ribonuclease HI B5Z0I8 RNH_ECO5E
100.0 Ribonuclease HI P0A7Y6 RNH_ECO57
100.0 Ribonuclease HI B7MBJ0 RNH_ECO45
100.0 Ribonuclease HI A7ZHV1 RNH_ECO24