Secondary structure and temperature-induced unfolding and refolding of ribonuclease T1 in aqueous solution. A Fourier transform infrared spectroscopic study.


Abstract

The secondary structure of ribonuclease T1 (RNase T1) in aqueous solution and its temperature-induced structural changes have been investigated by Fourier-transform infrared (FT-IR) spectroscopy. 13 to 14% alpha-helix and 32 to 33% beta-sheet were estimated from the resolution-enhanced FT-IR spectra, in agreement with the crystal structure which indicates 16% alpha-helix and 35% beta-sheet. Specific IR-marker bands are assigned to the different beta-sheet structures, to the slightly bent alpha-helix, and to beta-turn and irregular conformations present in RNase T1. The temperature dependence of the infrared spectra shows that the thermal unfolding and refolding of RNase T1 is fully reversible. This permitted the detailed analysis of structural changes that occur as a function of temperature by evaluating quantitatively the various secondary structure-related amide I band components and some amino acid side-chain vibrations as specific monitors. The secondary structure of RNase T1 is essentially retained in the temperature range between 20 and 50 degrees C. Significant perturbation of protein structure is initiated between 50 and 55 degrees C within regions of beta-sheet structures while the alpha-helix remains virtually intact up to 55 degrees C suggesting a "premelting" of RNase T1. Between 55 and 60 degrees C, a highly co-operative unfolding process is indicated by the simultaneous breakdown of all secondary structure components and by distinct changes of some specific side-chain vibrations. An analysis of the amide I band contour of RNase T1 at 70 degrees C proves that the unfolded state is predominantly, but not completely, irregular or "random coil". Residual, turn-like structures persisting even in the unfolded state are suggested by minor, turn related band components in the amide I region. From IR-spectra collected along a linear temperature gradient, intensity/temperature and frequency/temperature profiles were constructed using some peptide backbone and amino acid side-chain marker bands as local, structure-sensitive monitors. From these profiles individual transition temperatures tm and transition enthalpies delta H (van't Hoff) were calculated. The tm and delta H values revealed a small but distinct hysteresis between repetitive cycles of unfolding and refolding of the protein, suggesting slow refolding kinetics of RNase T1. Furthermore, the various infrared "marker bands" indicate a slightly different response towards temperature increase/decrease for different regions of the protein. The data demonstrate that infrared spectroscopy permits both the detailed analysis of structural changes occurring in a protein as a function of temperature and the determination of thermodynamic parameters characterizing its folded/unfolded state transition. Study holds ProTherm entries: 9264, 9265, 9266, 9267 Extra Details: H2O wad added in the experiment

Submission Details

ID: dRJM8t9k

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:37 p.m.

Version: 1

Publication Details
Fabian H;Schultz C;Naumann D;Landt O;Hahn U;Saenger W,J. Mol. Biol. (1993) Secondary structure and temperature-induced unfolding and refolding of ribonuclease T1 in aqueous solution. A Fourier transform infrared spectroscopic study. PMID:8355280
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
1YGW 1997-10-08 NMR STRUCTURE OF RIBONUCLEASE T1, 34 STRUCTURES
1IYY 2003-10-07 NMR STRUCTURE OF Gln25-RIBONUCLEASE T1, 24 STRUCTURES
1I0V 2001-02-14 1.23 Ribonuclease T1 in complex with 2'GMP (form I crystal)
4ODK 2015-01-14 1.4 Structure of SlyD from Thermus thermophilus in complex with T1 peptide
9RNT 1993-01-15 1.5 RIBONUCLEASE T1 WITH FREE RECOGNITION AND CATALYTIC SITE: CRYSTAL STRUCTURE ANALYSIS AT 1.5 ANGSTROMS RESOLUTION
1LOV 2002-08-21 1.55 X-ray structure of the E58A mutant of Ribonuclease T1 complexed with 3'-guanosine monophosphate
1LOY 2002-08-21 1.55 X-ray structure of the H40A/E58A mutant of Ribonuclease T1 complexed with 3'-guanosine monophosphate
1I0X 2001-02-14 1.65 RIBONUCLEASE T1 IN COMPLEX WITH 2'GMP (FORM II CRYSTAL)
4GSP 1998-08-12 1.65 RIBONUCLEASE T1 COMPLEXED WITH 2',3'-CGPS + 3'-GMP, 7 DAYS
1HYF 2001-02-14 1.7 RIBONUCLEASE T1 V16A MUTANT IN COMPLEX WITH SR2+
4BIR 1998-07-15 1.7 RIBONUCLEASE T1: FREE HIS92GLN MUTANT
1Q9E 2004-03-23 1.7 RNase T1 variant with adenine specificity
1RGA 1993-10-31 1.7 CRYSTAL STRUCTURE OF RNASE T1 WITH 3'-GMP AND GUANOSINE: A PRODUCT COMPLEX
1I3I 2001-03-07 1.76 Ribonuclease T1 V78T mutant
5BU4 1998-09-23 1.77 RIBONUCLEASE T1 COMPLEX WITH 2'GMP
3BU4 1998-09-23 1.77 RIBONUCLEASE T1 COMPLEX WITH 2'GMP
3RNT 1989-10-15 1.8 CRYSTAL STRUCTURE OF GUANOSINE-FREE RIBONUCLEASE T1, COMPLEXED WITH VANADATE(V), SUGGESTS CONFORMATIONAL CHANGE UPON SUBSTRATE BINDING
1BIR 1996-08-17 1.8 RIBONUCLEASE T1, PHE 100 TO ALA MUTANT COMPLEXED WITH 2' GMP
1RN4 1993-01-15 1.8 HIS92ALA MUTATION IN RIBONUCLEASE T1 INDUCES SEGMENTAL FLEXIBILITY. AN X-RAY STUDY
2AAE 1994-01-31 1.8 THE ROLE OF HISTIDINE-40 IN RIBONUCLEASE T1 CATALYSIS: THREE-DIMENSIONAL STRUCTURES OF THE PARTIALLY ACTIVE HIS40LYS MUTANT
1I2E 2001-03-07 1.8 Ribonuclease T1 V16A mutant, form I
5GSP 1998-03-18 1.8 RIBONUCLEASE T1/3'-GMP, 9 WEEKS
3BIR 1997-12-31 1.8 DISECTING HISTIDINE INTERACTIONS IN RIBONUCLEASE T1 BY ASN AND GLN SUBSTITUTIONS
8RNT 1993-01-15 1.8 STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH ZINC(II) AT 1.8 ANGSTROMS RESOLUTION: A ZN2+.6H2O.CARBOXYLATE CLATHRATE
4BU4 1998-09-23 1.8 RIBONUCLEASE T1 COMPLEX WITH 2'GMP
1FZU 2000-10-25 1.8 RNAse T1 V78A mutant
1HZ1 2001-01-31 1.8 RIBONUCLEASE T1 V16A MUTANT IN COMPLEX WITH MG2+
2RNT 1989-10-15 1.8 THREE-DIMENSIONAL STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH GUANYLYL-2(PRIME),5(PRIME)-GUANOSINE AT 1.8 ANGSTROMS RESOLUTION
2GSP 1998-08-12 1.8 RIBONUCLEASE T1/2',3'-CGPS AND 3'-GMP, 2 DAYS
1DET 1996-07-11 1.8 RIBONUCLEASE T1 CARBOXYMETHYLATED AT GLU 58 IN COMPLEX WITH 2'GMP
6RNT 1993-01-15 1.8 CRYSTAL STRUCTURE OF RIBONUCLEASE T1 COMPLEXED WITH ADENOSINE 2'-MONOPHOSPHATE AT 1.8-ANGSTROMS RESOLUTION
1RN1 1994-01-31 1.84 THREE-DIMENSIONAL STRUCTURE OF GLN 25-RIBONUCLEASE T1 AT 1.84 ANGSTROMS RESOLUTION: STRUCTURAL VARIATIONS AT THE BASE RECOGNITION AND CATALYTIC SITES
1I2G 2001-03-07 1.85 Ribonuclease T1 V16T mutant
1G02 2000-10-25 1.86 Ribonuclease T1 V16S mutant
1RGK 1993-01-15 1.87 RNASE T1 MUTANT GLU46GLN BINDS THE INHIBITORS 2'GMP AND 2'AMP AT THE 3' SUBSITE
3GSP 1998-08-12 1.9 RIBONUCLEASE T1 COMPLEXED WITH 2',3'-CGPS + 3'-GMP, 4 DAYS
1RLS 1994-12-20 1.9 CRYSTAL STRUCTURE OF RNASE T1 COMPLEXED WITH THE PRODUCT NUCLEOTIDE 3'-GMP. STRUCTURAL EVIDENCE FOR DIRECT INTERACTION OF HISTIDINE 40 AND GLUTAMIC ACID 58 WITH THE 2'-HYDROXYL GROUP OF RIBOSE
1LRA 1994-01-31 1.9 CRYSTALLOGRAPHIC STUDY OF GLU 58 ALA RNASE T1(ASTERISK)2'-GUANOSINE MONOPHOSPHATE AT 1.9 ANGSTROMS RESOLUTION
1LOW 2002-08-21 1.9 X-ray structure of the H40A mutant of Ribonuclease T1 complexed with 3'-guanosine monophosphate
1BU4 1999-02-16 1.9 RIBONUCLEASE 1 COMPLEX WITH 2'GMP
1RNT 1987-10-16 1.9 RESTRAINED LEAST-SQUARES REFINEMENT OF THE CRYSTAL STRUCTURE OF THE RIBONUCLEASE T1(ASTERISK)2(PRIME)-GUANYLIC ACID COMPLEX AT 1.9 ANGSTROMS RESOLUTION
2HOH 1998-09-23 1.9 RIBONUCLEASE T1 (N9A MUTANT) COMPLEXED WITH 2'GMP
1BVI 1998-09-23 1.9 RIBONUCLEASE T1 (WILDTYPE) COMPLEXED WITH 2'GMP
7RNT 1993-01-15 1.9 CRYSTAL STRUCTURE OF THE TYR45TRP MUTANT OF RIBONUCLEASE T1 IN A COMPLEX WITH 2'-ADENYLIC ACID
1RHL 1998-10-14 1.95 RIBONUCLEASE T1 COMPLEXED WITH 2'GMP/G23A MUTANT
3SYU 2012-03-28 1.95 Re-refined coordinates for pdb entry 1det - ribonuclease T1 carboxymethylated at GLU 58 in complex with 2'GMP
2BU4 1998-09-23 1.95 RIBONUCLEASE T1 COMPLEX WITH 2'GMP
3HOH 1998-09-16 1.95 RIBONUCLEASE T1 (THR93GLN MUTANT) COMPLEXED WITH 2'GMP
1I2F 2001-03-07 1.95 Ribonuclease T1 V16A mutant, form II
1RGC 1994-01-31 2.0 THE COMPLEX BETWEEN RIBONUCLEASE T1 AND 3'-GUANYLIC ACID SUGGESTS GEOMETRY OF ENZYMATIC REACTION PATH. AN X-RAY STUDY
5HOH 1998-09-23 2.0 RIBONUCLEASE T1 (ASN9ALA/THR93ALA DOUBLEMUTANT) COMPLEXED WITH 2'GMP
2AAD 1994-01-31 2.0 THE ROLE OF HISTIDINE-40 IN RIBONUCLEASE T1 CATALYSIS: THREE-DIMENSIONAL STRUCTURES OF THE PARTIALLY ACTIVE HIS40LYS MUTANT
1RGL 1993-01-15 2.0 RNASE T1 MUTANT GLU46GLN BINDS THE INHIBITORS 2'GMP AND 2'AMP AT THE 3' SUBSITE
1B2M 1999-03-25 2.0 THREE-DIMENSIONAL STRUCTURE OF RIBONULCEASE T1 COMPLEXED WITH AN ISOSTERIC PHOSPHONATE ANALOGUE OF GPU: ALTERNATE SUBSTRATE BINDING MODES AND CATALYSIS.
5BIR 1997-12-31 2.0 DISECTING HISTIDINE INTERACTIONS IN RIBONUCLEASE T1 USING ASN AND GLN MUTATIONS
7GSP 1998-03-18 2.0 RIBONUCLEASE T1/2',3'-CGPS, NON-PRODUCTIVE
1FYS 2000-10-25 2.0 Ribonuclease T1 V16C mutant
4HOH 1998-09-23 2.05 RIBONUCLEASE T1 (THR93ALA MUTANT) COMPLEXED WITH 2'GMP
1TTO 2005-09-06 2.1 Crystal structure of the Rnase T1 variant R2
4RNT 1992-01-15 2.2 HIS 92 ALA MUTATION IN RIBONUCLEASE T1 INDUCES SEGMENTAL FLEXIBILITY. AN X-RAY STUDY
6GSP 1998-03-18 2.2 RIBONUCLEASE T1/3'-GMP, 15 WEEKS
1GSP 1998-02-25 2.2 RIBONUCLEASE T1 COMPLEXED WITH 2',3'-CGPS, 1 DAY
1CH0 1999-12-22 2.3 RNASE T1 VARIANT WITH ALTERED GUANINE BINDING SEGMENT
1TRQ 1994-04-30 2.3 X-RAY CRYSTALLOGRAPHIC AND CALORIMERIC STUDIES OF THE EFFECTS OF THE MUTATION TRP 59 TYR IN RIBONUCLEASE T1
2BIR 1997-06-16 2.3 ADDITIVITY OF SUBSTRATE BINDING IN RIBONUCLEASE T1 (Y42A MUTANT)
1I3F 2001-03-07 2.35 Ribonuclease T1 V89S mutant
1TRP 1994-04-30 2.4 X-RAY CRYSTALLOGRAPHIC AND CALORIMERIC STUDIES OF THE EFFECTS OF THE MUTATION TRP 59 TYR IN RIBONUCLEASE T1
3URP 2012-03-28 3.19 Re-refinement of PDB entry 5RNT - ribonuclease T1 with guanosine-3',5'-diphosphate and phosphate ion bound
5RNT 1993-01-15 3.2 X-RAY ANALYSIS OF CUBIC CRYSTALS OF THE COMPLEX FORMED BETWEEN RIBONUCLEASE T1 AND GUANOSINE-3',5'-BISPHOSPHATE

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Guanyl-specific ribonuclease T1 P00651 RNT1_ASPOR