SummaryThe nucleotide sequence of the structural gene,scrA, which codes for sucrose‐specific EnzymellScr(EIIScr) of the phosphoenolpyruvate‐dependent carbohydrate: phosphotransferase system (PTS), was determined. EllScrrequires an Enzymelll, the product of the genecrr, for full activity. The genescrAis preceded immediately by a classical Shine‐Dalgarno sequence (AAGAGGGTA). It contains 1368 nucleotides with an increased GC‐content (58%) corresponding to a polypeptide of 455 amino acid residues (Mr47 500). The protein has the hydropathic profile (average hydropathy +0.82) of an integral membrane protein lacking extended α‐helical structures and a signal peptide. Comparison with the sequence of the β‐glucoside‐specific Enzymell (EllBgl, 625 amino acids, Mr66480; Bramley and Kornberg, 1987a; Schnetzet al., 1987) revealed strong homologies between EllScrand the first 458 residues of EllBgl. The 162 carboxyterminal residues of EllBgl, however, showed a high homology with the sequence of Enzymelll (Nelsonet al., 1984), a homology also described recently by Bramley and Kornberg (1987b). The evolutionary and functional significance of the similarities with four other Enzymes