Low frequency dynamics of Cystathionine beta-synthase

Femtosecond coherence spectroscopy is used to study the low frequency dynamics of cystathionine beta-synthase (CBS). CBS is a pyridoxal-5′-phosphate-dependent heme enzyme with cysteine and histidine axial ligands that catalyzes the condensation of serine and homocysteine to form cystathionine. Resonance excitation near the maximum of the ferric state Soret band reveals a mode near ∼40 cm−1 (phase ∼pi/2). The phase indicates that the initial...