Lumbricin I, a novel proline-rich antimicrobial peptide from the earthworm: purification, cDNA cloning and molecular characterization.
A novel antimicrobial peptide was isolated and characterized from the earthworm, Lumbricus rubellus. The antimicrobial peptide was purified to homogeneity by a heparin-affinity column and C18 reverse-phase HPLC, and named lumbricin I. Lumbricin I was a proline-rich antimicrobial peptide of 62 amino acids (15% proline in molar ratio; molecular mass, 7231 Da), whose complete sequence was determined by a combination of peptide sequence and cDNA analysis. The peptide and cDNA sequence analysis revealed that lumbricin I was produced as a precursor form consisting of 76 amino acids, with 14 residues in a presegment and 62 residues in mature lumbricin I. Lumbricin I showed antimicrobial activity in vitro against a broad spectrum of microorganisms without hemolytic activity. In addition, a 29-amino acid peptide, named lumbricin I(6-34), which was derived from residues 6-34 of lumbricin I, showed marginally stronger antimicrobial activity than lumbricin I. Northern blot analysis on total RNA revealed that expression of lumbricin I gene was not induced by bacterial infection, but was constitutively expressed. Furthermore, the expression of lumbricin I gene was specific in adult L. rubellus: Lumbricin I mRNA was detected only in adult L. rubellus, but not in eggs and young L. rubellus.
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 373-1 Yusong-gu Kusong-dong, Taejon 305-701, South Korea.
J H
JH
Cho
C B
CB
Park
Y G
YG
Yoon
S C
SC
Kim
D000595:Amino Acid Sequence; D000818:Animals; D000845:Annelida; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005658:Fungi / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D007865:Leeches; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009835:Oligochaeta / Q000235:genetics; D009865:Oocytes / Q000502:physiology; D010455:Peptides; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000032:analysis* / Q000737:chemistry* / Q000235:genetics* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000494:pharmacology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D018076:DNA, Complementary; D010455:Peptides; D011506:Proteins; D011994:Recombinant Proteins; C115676:lumbricin I