  The rates of protein folding with photon absorption or emission and the cross
section of photon -protein inelastic scattering are calculated from the quantum
folding theory by use of standard field-theoretical method. All these protein
photo-folding processes are compared with common protein folding without
interaction of photons (nonradiative folding). It is demonstrated that there
exists a common factor (thermo-averaged overlap integral of vibration wave
function, TAOI) for protein folding and protein photo-folding. Based on this
finding it is predicted that: 1) the stimulated photo-folding rates show the
same temperature dependence as protein folding; 2) the spectral line of
electronic transition is broadened to a band which includes abundant vibration
spectrum without and with conformational transition and the width of the
vibration spectral line is largely reduced; 3) the resonance fluorescence cross
section changes with temperature obeying the same law (Luo-Lu's law). The
particular form of the folding rate - temperature relation and the abundant
spectral structure imply the existence of a set of quantum oscillators in the
transition process and these oscillators are mainly of torsion type of low
frequency, imply the quantum tunneling between protein conformations does exist
in folding and photo-folding processes and the tunneling is rooted deeply in
the coherent motion of the conformational-electronic system.
