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Abstract

The primary structure of the histidine‐containing phosphocarrier protein HPr of the phosphoenol‐pyruvate‐dependent phosphotransferase system from Staphylococcus aureus was determined by automated Edman degradation. The complete sequence was deduced from the direct analysis of the protein by automated Edman degradation in a liquid‐phase sequencer of Edman and from the sequence of tryptic, thermolytic and cyanogen bromide peptides as obtained by automated Edman degradation in a solid‐phase sequencer of Laursen. The amino‐acid sequence was found to be Met‐Glu‐Gln‐Asn‐Ser‐Tyr‐Val‐Ile‐Ile‐Asp‐Glu‐Thr‐Gly‐Ile‐His‐Ala‐Arg‐Pro‐Ala‐Thr‐Met‐Leu‐Val‐Gln‐Thr‐Ala‐Ser‐Lys‐Phe‐Asp‐Ser‐Ile‐Asp‐Gln‐Gly‐Gly‐Tyr‐Asp‐Ser‐Met‐Gln‐Leu‐Lys‐Ser‐Leu‐Gly‐Val‐Gly‐Lys‐Asp‐Glu‐Glu‐Ile‐Thr‐Ile‐Tyr‐Ser‐Ala‐Asp‐Lys‐Lys‐Glu‐Gly‐Leu‐Thr‐Lys‐Met‐Ser‐Ile‐Val. The 70 residues correspond to a molecular weight of 7685.

The one histidine involved in the phosphotransfer reaction of this protein was found at position 15 as part of a region of the sequence which has no predictable secondary structure. It is suggested that this protein belongs to the group of male proteins with the active center located on a protrusion rather than a cleft.