PMAP-37, a novel antibacterial peptide from pig myeloid cells. cDNA cloning, chemical synthesis and activity.
A molecular biological approach, based on preproregion homology in the precursors of several diverse antibacterial peptides, was used to clone a pig bone marrow cDNA encoding a novel 167-residue polypeptide. The preproregion of this polypeptide is highly similar to corresponding regions in congeners from pig, cattle and rabbit. It is followed by a unique, cationic, 37-residue sequence, which was predicted to have a high propensity for an alpha-helical conformation. A peptide, termed PMAP-37, corresponding to this sequence, was chemically synthesized and shown to undergo a transition from a random coil to an ordered, mainly helical, conformation on addition of trifluoroethanol. This behaviour is typical of an amphipathic alpha helix, a structure common to several membrane-active, antimicrobial peptides. In vitro experiments showed that PMAP-37 strongly inhibits the growth of several strains of Gram-negative and Gram-positive bacteria, with minimal inhibitory concentrations ranging over 1-4 microM, and permeabilizes the inner membrane of Escherichia coli. Interestingly, the 15-32 stretch of PMAP-37 show a remarkable similarity to N-terminal stretches in cecropins B and A from Drosophila melanogaster and Cecropia hyalophora, respectively. This affords an uncommon example of sequence convergence.
Tossi
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Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università di Trieste, Italy.
Scocchi
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Zanetti
M
M
Storici
P
P
Gennaro
R
R
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011506:Proteins / Q000138:chemical synthesis / Q000235:genetics* / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013552:Swine
D000900:Anti-Bacterial Agents; D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D011506:Proteins; C093365:PMAP-37