Differential scanning calorimetry of the unfolding of myosin subfragment 1, subfragment 2, and heavy meromyosin.


The thermal unfolding of rabbit skeletal heavy meromyosin (HMM), myosin subfragment 1, and subfragment 2 has been studied by differential scanning calorimetry (DSC). Two distinct endotherms are observed in the DSC scan of heavy meromyosin. The first endotherm, with a Tm of 41 degrees C at pH 7.9 in 0.1 M KCl, is assigned to the unfolding of the subfragment 2 domain of HMM based on scans of isolated subfragment 2. The unfolding of the subfragment 2 domain is reversible both in the isolated form and in HMM. The unfolding of subfragment 2 in HMM can be fit as a single two-state transition with a delta Hvh and delta Hcal of 161 kcal/mol, indicating that subfragment 2 exists as a single domain in HMM. The unfolding of subfragment 2 is characterized by an extraordinarily large delta Cp of approximately 30,000 cal/(deg.mol). In the presence of nucleotides, the high-temperature HMM endotherm with a Tm of 48 degrees C shifts to higher temperature, indicating that this peak corresponds to the unfolding of the subfragment 1 domain. This assignment has been confirmed by comparison with isolated subfragment 1. The stabilizing effect of AMPPNP was significantly greater than that of ADP. The vanadate-trapped ADP species was slightly more stable than M.AMPPNP with a Tm at 58 degrees C. The unfolding of subfragment 1, both in the isolated form and in HMM, was irreversible. Only a single endotherm was noted in the DSC scans of the subfragment 1 domain of HMM and in freshly prepared subfragment 1 complexes.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 3676, 3677, 3678, 3679 Extra Details: endotherms; single two-state transition; stabilizing effect;,binding of nucleotides

Submission Details

ID: rUpx4kp93

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:22 p.m.

Version: 1

Publication Details
Shriver JW;Kamath U,Biochemistry (1990) Differential scanning calorimetry of the unfolding of myosin subfragment 1, subfragment 2, and heavy meromyosin. PMID:2185830
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 UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
98.6 A Calmodulin O16305 CALM_CAEEL
99.3 A Calmodulin P62147 CALM1_BRAFL
99.3 A Calmodulin P62148 CALM1_BRALA
99.3 A Calmodulin P62153 CALMA_HALRO
99.3 A Calmodulin P62145 CALM_APLCA
99.3 A Calmodulin P62152 CALM_DROME
99.3 A Calmodulin P62154 CALM_LOCMI
98.0 A Calmodulin Q8STF0 CALM_STRIE
98.3 A Calmodulin P0DP23 CALM1_HUMAN
98.3 A Calmodulin P0DP26 CALM1_MOUSE
98.3 A Calmodulin P0DP29 CALM1_RAT
98.3 A Calmodulin P0DP33 CALM1_XENLA
99.1 A Calmodulin Q9UB37 CALM2_BRALA
98.3 A Calmodulin P0DP24 CALM2_HUMAN
98.3 A Calmodulin P0DP27 CALM2_MOUSE
98.3 A Calmodulin P0DP30 CALM2_RAT
98.3 A Calmodulin P0DP25 CALM3_HUMAN
98.3 A Calmodulin P0DP28 CALM3_MOUSE
98.3 A Calmodulin P0DP31 CALM3_RAT
98.3 A Calmodulin P62144 CALM_ANAPL
98.3 A Calmodulin P62157 CALM_BOVIN
98.3 A Calmodulin P62149 CALM_CHICK
98.3 A Calmodulin Q6IT78 CALM_CTEID
98.3 A Calmodulin Q6PI52 CALM_DANRE
98.3 A Calmodulin P62156 CALM_ONCSP
98.3 A Calmodulin Q71UH6 CALM_PERFV
98.3 A Calmodulin Q5RAD2 CALM_PONAB
98.3 A Calmodulin P62160 CALM_RABIT
98.3 A Calmodulin Q6YNX6 CALM_SHEEP
98.3 A Calmodulin P21251 CALM_STIJA
98.3 A Calmodulin P62151 CALM_TETCF
98.3 A Calmodulin P0DP34 CAM2A_XENLA
98.3 A Calmodulin P0DP35 CAM2B_XENLA
97.4 A Calmodulin Q7T3T2 CALM_EPIAK
98.3 A Calmodulin Q95NR9 CALM_METSE
92.6 A Calmodulin P62146 CALMA_ARBPU
92.6 A Calmodulin O96081 CALMB_HALRO
92.6 A Calmodulin A4UHC0 CALM_ALEFU
92.6 A Calmodulin A3E4F9 CALM_KARVE
92.6 A Calmodulin A3E3H0 CALM_PFIPI
92.6 A Calmodulin A3E4D8 CALM_PROMN
92.6 A Calmodulin P02598 CALM_TETPY
91.2 A Calmodulin A8I1Q0 CALM_HETTR
91.2 A Calmodulin O97341 CALM_SUBDO
91.2 A Calmodulin P27166 CALM_STYLE
95.7 A Calmodulin O02367 CALM_CIOIN
91.9 A Calmodulin P62150 CALM_ORYLA
100.0 A Calmodulin Q40302 CALM_MACPY
96.5 A Calmodulin Q9HFY6 CALM_BLAEM
91.4 A Calmodulin P05932 CALMB_ARBPU
100.0 A Calmodulin P02594 CALM_ELEEL
94.2 A Calmodulin P11118 CALM_EUGGR
92.3 A Calmodulin P53440 CALMF_NAEGR
100.0 A Calmodulin P02595 CALM_PATSP
100.0 A Calmodulin P11121 CALM_PYUSP
100.0 A Calmodulin P62184 CALM_RENRE
93.5 A Calmodulin P69097 CALM_TRYBB
93.5 A Calmodulin P69098 CALM_TRYBG
93.5 A Calmodulin P18061 CALM_TRYCR
100.0 B Calmodulin A4IFM7 MYLK2_BOVIN
100.0 B Calmodulin Q9H1R3 MYLK2_HUMAN
100.0 B Calmodulin Q8VCR8 MYLK2_MOUSE
100.0 B Calmodulin P07313 MYLK2_RABIT
100.0 B Calmodulin P20689 MYLK2_RAT