Assessing the prospect of XAFS experiments of metalloproteins under in vivo conditions at Indus‐2 synchrotron facility, India

The feasibility of X‐ray absorption fine‐structure (XAFS) experiments of ultra‐dilute metalloproteins under in vivo conditions (T = 300 K, pH = 7) at the BL‐9 bending‐magnet beamline (Indus‐2) is reported, using as an example analogous synthetic Zn (0.1 mM) M1dr solution. The (Zn K‐edge) XAFS of M1dr solution was measured with a four‐element silicon drift detector. The first‐shell fit was tested and found to be robust against statistical noise, generating reliable nearest‐neighbor bond results. The results are found to be invariant between physiological and non‐physiological conditions, which confirms the robust coordination chemistry of Zn with important biological implications. The scope of improving spectral quality for accommodation of higher‐shell analysis is addressed. The feasibility of X‐ray absorption fine‐structure (XAFS) experiments of ultra‐dilute metalloprotein solutions at Indus‐2 is evaluated.