An Isomorphous Heavy-Atom Derivative of Crystalline Formylmethionine Transfer RNA

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Science  04 Aug 1972:
Vol. 177, Issue 4047, pp. 429-431
DOI: 10.1126/science.177.4047.429


An isomorphous osmium derivative of crystalline yeast initiator transfer RNA has been prepared and interpreted to 6-angstrom resolution. The coordinates of the heavy atoms have been determined by Patterson and "direct" methods applied to the difference coefficients of the centric projections, followed by least-squares refinement. There is one dominant site per asymmetric unit, consistent with the finding by neutron-activation analysis that there is approximately one osmium atom per molecule of transfer RNA. The osmium derivative appears to be a normal substrate for enzymatic aminoacylation.