Thermally induced unfolding of Acanthamoeba myosin II and skeletal muscle myosin: nucleotide effects.


The thermal unfolding of monomeric Acanthamoeba myosin II and rabbit skeletal muscle myosin at pH 7.5 in 0.6 M KCl has been studied by differential scanning calorimetry (DSC) and circular dichroism. A single endotherm (at approximately 40 to 45 degrees C) with a maximum at 41.7 +/- 0.1 degrees C and delta H approximately 1080 +/- kcal/mol is observed for both dephospho- and phospho-myosin II. Skeletal muscle myosin unfolds with less cooperativity over a wider temperature range (approximately 40 to 60 degrees C) with delta H approximately 2500 kcal/mol. The thermal unfolding of either myosin results in a loss of approximately 70% of alpha-helical structures. Saturation of dephospho- or phospho-myosin II with 5'-adenylylimidodiphosphate (AMPPNP) in the presence of Mg2+ produces a second endotherm with a maximum at approximately 49 degrees C. The latter observation is attributed to a stabilization of head regions by nucleotide binding. Indeed, a purified N-terminal myosin II head fragment has been found to unfold with Tmax approximately 41 and approximately 48 degrees C in the absence and presence of AMPPNP, respectively. The stabilization of the head regions is less with ADP+Pi and still smaller with ADP alone. In summary, thermally induced unfolding of myosin II is affected by nucleotide binding to heads, but not by phosphorylation or even removal of a 66-amino-acid tailpiece containing phosphorylation sites. The observed differences in the cooperativity of unfolding myosin II and skeletal muscle myosin relate to differences between rod structures and possibly also head-rod interactions. Study holds ProTherm entries: 7736, 7737, 7738, 7739 Extra Details: differential scanning calorimetry; protein folding;,ATP binding; circular dichroism; myosin

Submission Details

ID: d9v2BMps

Submitter: Connie Wang

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

Version: 1

Publication Details
Zolkiewski M;Redowicz MJ;Korn ED;Ginsburg A,Arch. Biochem. Biophys. (1995) Thermally induced unfolding of Acanthamoeba myosin II and skeletal muscle myosin: nucleotide effects. PMID:7726563
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