Far-UV circular dichroism spectra of human β-cardiac myosin S2 (residues 839–968): wild type and four single-cysteine constructs

Far-UV circular dichroism (CD) spectra of the S2 fragment of human beta-cardiac myosin (MYH7, residues 839–968, UniProt P12883): wild type and the constructs C905A, C947A, S879C (S879C/C905A/C947A) and A850C (A850C/C905A/C947A). Spectra were recorded on 2025-08-19 on a Jasco J-1500 spectropolarimeter (PTC-517 Peltier) at 25 °C in 50 mM sodium phosphate, 50 mM NaCl, pH 7.4, in a 0.1 cm quartz cell (260–200 nm, 0.5 nm step, 1 nm bandwidth, 4 s digital integration time, 20 nm/min, 3 accumulations averaged). A buffer baseline recorded the same day was subtracted; no smoothing was applied. For each construct the dataset contains the baseline-subtracted spectrum (mdeg, mean residue ellipticity, delta epsilon and HT voltage), the raw sample scan, the buffer baseline, the sequence, and the original Jasco .jws files. Protein concentration is nominal (10 µM, as entered at acquisition) and was not independently verified; mean residue ellipticity and delta epsilon use this nominal value, so absolute magnitudes are uncertain. In the associated article the spectra are used for shape only and are shown normalized at 222 nm. Associated article: "Structural Organization and Energetics of Proximal S2 Dimerization in Cardiac Myosin", submitted to Biophysical Journal.