Study of effects of pH on the stability of domains in myosin rod by high-resolution differential scanning calorimetry.


Abstract

Differential scanning calorimetry (DSC) has detected at least six quasi-independent structure domains in myosin rod [Potekhin, S.A., & Privalov, P.L. (1978) Biofizika 23, 219-223]. These domains were found to be remarkably sensitive to pH in the physiological range, i.e., pH 6-8. We compared the thermodynamic characteristics, and studied effects of pH on the stability, of individual domains in rod, light meromyosin (LMM), and subfragment 2 (S-2). In rod, the lowest stability domain (approximately 400 amino acid residues per double strand), with a Tm of 42.4 degrees C, a delta Hcal of 190 kcal/mol, and a delta G of 3.39 kcal/mol, at pH 7.02, destabilized by absorption of protons, is located at the LMM/S-2 junction and split into two parts, one associated with S-2 (approximately 100 residues per double strand) and the other with LMM (300 residues per double strand). The fragment with S-2 is likely a part of the "hinge" suggested by Swenson and Ritchie [(1980) Biochemistry 19, 5371-5375]. All other domains of rod released protons on melting. The domains located in S-2 were the most sensitive to pH and released a total of 0.9 proton on melting. The thermal meltings of all domains in myosin rod, LMM, and S-2 were independent of each other, and enthalpies of melting were additive in the whole pH range studied. Their sensitivities to pH and KCl were also unaffected by the presence or absence of other fragments. For example, domains in an isolated S-2 behaved similarly as they were in the rod, and so were domains in LMM.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 4095, 4096, 4097, 4098, 4099, 4100, 4101, 4102, 4103, 4104, 4105, 4106, 4107, 4108, 4109, 4110, 4111, 4112, 4113, 4114, 4115, 4116, 4117, 4118, 4119, 4120, 4121, 4122, 4123, 4124, 4125, 4126, 4127, 4128, 4129, 4130, 4131, 4132, 4133, 4134, 4135, 4136, 4137, 4138, 4139, 4140, 4141, 4142, 4143, 4144, 4145, 4146, 4147, 4148, 4149, 4150, 4151, 4152, 4153, 4154, 4155, 4156, 4157, 4158, 4159, 4160, 4161, 4162, 4163, 4164, 4165, 4166, 4167, 4168, 4169, 4170, 4171, 4172, 4173, 4174, 4175, 4176, 4177, 4178, 4179, 4180 Extra Details: additive : EDTA(1 mM), quasi-independent structure domains; hinge; fragments;,protonation; histidine residue

Submission Details

ID: SKvZ5gGx

Submitter: Connie Wang

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

Version: 1

Publication Details
Bertazzon A;Tsong TY,Biochemistry (1990) Study of effects of pH on the stability of domains in myosin rod by high-resolution differential scanning calorimetry. PMID:2207086
Additional Information

Number of data points 213
Proteins Calmodulin ; Myosin light chain kinase 2, skeletal/cardiac muscle
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: dCp pH:7.02 ; Experimental Assay: dCp pH:6.79 ; Experimental Assay: dHcal pH:6.79 ; Experimental Assay: Tm pH:6.79 ; Experimental Assay: dCp pH:6.45 ; Experimental Assay: dCp pH:7.03 ; Experimental Assay: dHcal pH:7.03 ; Experimental Assay: Tm pH:7.03 ; Experimental Assay: dCp pH:6.75 ; Experimental Assay: dHcal pH:6.75 ; Experimental Assay: Tm pH:6.75 ; Experimental Assay: dCp pH:6.4 ; Experimental Assay: dHcal pH:6.4 ; Experimental Assay: Tm pH:6.4 ; Experimental Assay: dCp pH:6.23 ; Experimental Assay: dHcal pH:6.23 ; Experimental Assay: Tm pH:6.23 ; Experimental Assay: dHcal pH:7.31 ; Experimental Assay: Tm pH:7.31 ; Experimental Assay: dHvH pH:7.31 ; Experimental Assay: dHcal pH:7.02 ; Experimental Assay: Tm pH:7.02 ; Experimental Assay: dHvH pH:7.02 ; Experimental Assay: dHcal pH:6.95 ; Experimental Assay: Tm pH:6.95 ; Experimental Assay: dHvH pH:6.95 ; Experimental Assay: dHcal pH:6.85 ; Experimental Assay: Tm pH:6.85 ; Experimental Assay: dHvH pH:6.85 ; Experimental Assay: dHcal pH:6.65 ; Experimental Assay: Tm pH:6.65 ; Experimental Assay: dHvH pH:6.65 ; Experimental Assay: dHcal pH:6.45 ; Experimental Assay: Tm pH:6.45 ; Experimental Assay: dHvH pH:6.45 ; Experimental Assay: dHcal pH:6.35 ; Experimental Assay: Tm pH:6.35 ; Experimental Assay: dHvH pH:6.35 ; Experimental Assay: dHcal pH:6.15 ; Experimental Assay: Tm pH:6.15 ; Experimental Assay: dHvH pH:6.15 ; Experimental Assay: dHcal pH:6.03 ; Experimental Assay: Tm pH:6.03 ; Experimental Assay: dHvH pH:6.03
Libraries Mutations for sequence A:ADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEVDADGNGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGFISAAELRHVMTNLGEKLTDEEVDEMIREADIDGDGQVNYEEFVTMMTSK/B:KRRWKKNFIAVSAANRFKKISSSGAL
Sequence Assay Result Units