Cho J H, Park C B, Yoon Y G, Kim S C
Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 373-1 Yusong-gu Kusong-dong, Taejon 305-701, South Korea.
Biochim Biophys Acta. 1998 Oct 22;1408(1):67-76. doi: 10.1016/s0925-4439(98)00058-1.
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.
从赤子爱胜蚓中分离并鉴定出一种新型抗菌肽。该抗菌肽通过肝素亲和柱和C18反相高效液相色谱法纯化至同质，并命名为蚓抗菌肽I。蚓抗菌肽I是一种富含脯氨酸的抗菌肽，由62个氨基酸组成（摩尔比中脯氨酸占15%；分子量为7231 Da），其完整序列通过肽序列和cDNA分析相结合的方法确定。肽和cDNA序列分析表明，蚓抗菌肽I以前体形式产生，由76个氨基酸组成，前导序列中有14个残基，成熟的蚓抗菌肽I中有62个残基。蚓抗菌肽I在体外对多种微生物具有抗菌活性，且无溶血活性。此外，一种由蚓抗菌肽I的6-34位残基衍生而来的29个氨基酸的肽，命名为蚓抗菌肽I(6-34)，其抗菌活性略强于蚓抗菌肽I。对总RNA的Northern印迹分析表明，蚓抗菌肽I基因的表达不是由细菌感染诱导的，而是组成性表达的。此外，蚓抗菌肽I基因的表达在成年赤子爱胜蚓中具有特异性：仅在成年赤子爱胜蚓中检测到蚓抗菌肽I mRNA，而在卵和幼体赤子爱胜蚓中未检测到。
