However , replacement of all methionines by selenomethionines is a widely used , recent technique in solving the phase problem during X-ray crystallographic structure determination of many proteins ( MAD - phasing ) .
Proteins containing such unspecifically incorporated selenomethionine residues are not regarded as selenoproteins .
Replacement of all methionines by selenomethionines is a widely used , recent technique in solving the phase problem during X-ray crystallographic structure determination of many proteins ( MAD - phasing ) .
Proteins containing such unspecifically incorporated selenomethionine residues are not regarded as selenoproteins .