Dear phenix developers and users, I wanted to ask if there is a possibility to considerably distinguish betwenn two/three metals. I crystallized an iron-binding protein (transferrin in apo form) with a Ru- and Ga-compound. I see density in the metal-binding site which should come from the Ru/Ga metal since crystallization was done with the apo-form, but nevertheless I need to prove this. The wavelength of the X-ray was 1.02 Angstrom and the respective f''and f' values for the metals are +1.66e/+0.30e (Fe), +1.62/-0.5 (Ru) and +2.95/-0.76 (Ga). Is it possible to distinguish between Ru/Ga and Fe and thus to prove that Fe was not bound? The resolution is moderate with 3.1 angstrom and all metals are able to exhibit the same coordination geometry, thus you cannot distinguish according to the geometry. Unfortunately, I was also not able to measure the crystal with multiple wavelenghts because the crystals were very fragile. I hope you can help me and give me some advice. Thank you in advance. Best Regards, Aleks -- Aleksandar Bijelic, MSc. Institut für Biophysikalische Chemie Universität Wien Althanstrasse 14 1090 Wien Tel: +43 1 4277 52536 e-Mail:[email protected]