The C-terminal bisphosphorylated proenkephalin-A-(209-237)-peptide from adrenal medullary chromaffin granules possesses antibacterial activity.
The chromaffin granules have been shown to be an excellent model to study the processing of proenkephalin-A and chromogranins. Recently, we reported a study dealing with the processing of chromogranin B/secretogranin I and the occurrence of the C-terminal chromogranin B-derived peptide 614-626 which was shown to have antibacterial activity [Strub, J.M., Garcia-Sablone, P., Looning, K., Taupenot, L., Hubert, P., Van Dorsselaer, A., Aunis, D. & Metz-Boutigue, M.H. (1995) Eur. J. Biochem. 229, 356-368]. We also observed that this new antibacterial activity present in chromaffin granules was associated with other endogenous protein-derived fragments yet to be characterized. The present study reports the isolation and characterization of a peptide which possesses antibacterial activity and which corresponds to the C-terminal 209-237 sequence of proenkephalin-A. A detailed study using microsequencing and matrix-assisted-laser-desorption time-of-flight mass spectrometry (MALD-TOF MS) allowed us to correlate the antibacterial activity of this peptide named enkelytin (FAEPLPSEEEGESYSKEVPEMEKRYGGFM) with post-translational modifications. Endogenous bisphosphorylated proenkephalin-A-(209-237) was active on Micrococcus luteus and Bacillus megaterium killing bacteria in the 0.2 - 0.4 microM range but was inactive in similar conditions towards Escherichia coli. Enkelytin shares sequence and structural similarities with the antibacterial C-terminal domain of diazepam-binding inhibitor. According to this similarity, a prediction of secondary structure is proposed for enkelytin and discussed in relationship to its biological activity.
Goumon
Y
Y
Institut National de la Santé et de la Recherche Médicale, Unité 338 de Biologie de la Communication Cellulaire, Strasbourg, France.
Strub
J M
JM
Moniatte
M
M
Nullans
G
G
Poteur
L
L
Hubert
P
P
Van Dorsselaer
A
A
Aunis
D
D
Metz-Boutigue
M H
MH
D000313:Adrenal Medulla / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D002417:Cattle; D002837:Chromaffin Granules / Q000378:metabolism*; D004745:Enkephalins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology*; D010766:Phosphorylation; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000900:Anti-Bacterial Agents; D004745:Enkephalins; D010446:Peptide Fragments; C099820:enkelytin