A scanning calorimetric study of unfolding equilibria in homodimeric chicken gizzard tropomyosins.


Abstract

Using both circular dichroism (CD) and differential scanning calorimetry (DSC), several laboratories find that the thermal unfolding transitions of alpha alpha and beta beta homodimeric coiled coils of rabbit tropomyosin are multistate and display an overall unfolding enthalpy of near 300 kcal (mol dimer)(-1). In contrast, an extant CD study of beta beta and gamma gamma species of chicken gizzard tropomyosin concludes that their unfolding transitions are simple two-state transitions, with much smaller overall enthalpies (98 kcal mol(-1) for beta beta and 162 kcal mol(-1) for gamma gamma). However, these smaller enthalpies have been questioned, because they imply a concentration dependence of the melting temperatures that is far larger than observed by CD. We report here DSC studies of the unfolding of both beta beta and gamma gamma chicken gizzard homodimers. The results show that these transitions are very similar to those in rabbit tropomyosins in that 1) the overall unfolding enthalpy is near 300 kcal mol(-1); 2) the overall delta C(rho) values are significantly positive; 3) the various transitions are multistate, requiring at least two and as many as four domains to fit the DSC data. DSC studies are also reported on these homodimeric species of chicken gizzard tropomyosin with a single interchain disulfide cross-link. These results are also generally similar to those for the correspondingly cross-linked rabbit tropomyosins. Study holds ProTherm entries: 7412, 7413, 7414, 7415 Extra Details: additive : EDTA(10 mM),

Submission Details

ID: 4gZag8Mv3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:34 p.m.

Version: 1

Publication Details
O'Brien R;Sturtevant JM;Wrabl J;Holtzer ME;Holtzer A,Biophys. J. (1996) A scanning calorimetric study of unfolding equilibria in homodimeric chicken gizzard tropomyosins. PMID:9172766
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
6OTN 2019-05-03T00:00:00+0000 2.4 Crystal Structure of an N-terminal Fragment of Cancer Associated Tropomyosin 3.1 (Tpm3.1)
7NEP 2021-02-04T00:00:00+0000 10.2 Homology model of the in situ actomyosin complex from the A-band of mouse psoas muscle sarcomere in the rigor state
1KQL 2002-01-07T00:00:00+0000 2.7 Crystal structure of the C-terminal region of striated muscle alpha-tropomyosin at 2.7 angstrom resolution
1MV4 2002-09-24T00:00:00+0000 0 TM9A251-284: A Peptide Model of the C-Terminus of a Rat Striated Alpha Tropomyosin
2B9C 2005-10-11T00:00:00+0000 2.3 Structure of tropomyosin's mid-region: bending and binding sites for actin
2G9J 2006-03-06T00:00:00+0000 0 Complex of TM1a(1-14)Zip with TM9a(251-284): a model for the polymerization domain ("overlap region") of tropomyosin, Northeast Structural Genomics Target OR9
2G9J 2006-03-06T00:00:00+0000 0 Complex of TM1a(1-14)Zip with TM9a(251-284): a model for the polymerization domain ("overlap region") of tropomyosin, Northeast Structural Genomics Target OR9
1C1G 1999-07-22T00:00:00+0000 7.0 CRYSTAL STRUCTURE OF TROPOMYOSIN AT 7 ANGSTROMS RESOLUTION IN THE SPERMINE-INDUCED CRYSTAL FORM
1IC2 2001-03-29T00:00:00+0000 2.0 DECIPHERING THE DESIGN OF THE TROPOMYOSIN MOLECULE
3MTU 2010-04-30T00:00:00+0000 2.1 Structure of the Tropomyosin Overlap Complex from Chicken Smooth Muscle

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Tropomyosin alpha-1 chain Q01173 TPM1_XENLA
100.0 Tropomyosin alpha-1 chain P04692 TPM1_RAT
100.0 Tropomyosin alpha-1 chain P13105 TPM1_RANTE
100.0 Tropomyosin alpha-1 chain P58772 TPM1_RABIT
100.0 Tropomyosin alpha-1 chain P42639 TPM1_PIG
100.0 Tropomyosin alpha-1 chain P58771 TPM1_MOUSE
100.0 Tropomyosin alpha-1 chain P09493 TPM1_HUMAN
100.0 Tropomyosin alpha-1 chain P13104 TPM1_DANRE
100.0 Tropomyosin alpha-1 chain P58773 TPM1_COTJA
100.0 Tropomyosin alpha-1 chain P04268 TPM1_CHICK
100.0 Tropomyosin alpha-1 chain P84335 TPM1_CHEAU
100.0 Tropomyosin alpha-1 chain Q5KR49 TPM1_BOVIN
100.0 Tropomyosin alpha-1 chain A1XQV4 TPM3_PIG
100.0 Tropomyosin alpha-1 chain P06753 TPM3_HUMAN
100.0 Tropomyosin alpha-1 chain Q5KR47 TPM3_BOVIN