our data show that the guanine nucleotide binding domain of ef-tu ( 30 % alpha-helix and 16 % beta-pleated sheet for the gdp complex ) has quite a different secondary structure composition than the ras proteins ( e.g. , the cellular ras protein has 47 % alpha-helix and 22 % beta-pleated sheet for the gdp complex ) , indicating that the protein core comprising the guanine nucleotide binding site might be similar but that major structural differences must exist at the portion outside this core .
C0018340
gdp
C0018328
guanine nucleotide