Isolation, purification and de novo sequencing of TBD-1, the first beta-defensin from leukocytes of reptiles.

A novel peptide with antimicrobial activity was isolated from leukocytes of the European pond turtle Emys orbicularis and purified to homogeneity by preparative gel electrophoresis followed by reversed phase chromatography. It was highly active in vitro against Escherichia coli, Listeria monocytogenes, methicillin-resistant Staphylococcus aureus, and Candida albicans. The isolated peptide was sequenced de novo by tandem mass spectrometry using both collision-induced and electron-transfer dissociation in combination with different chemical derivatization techniques.

Aurelin, a novel antimicrobial peptide from jellyfish Aurelia aurita with structural features of defensins and channel-blocking toxins.

A novel 40-residue antimicrobial peptide, aurelin, exhibiting activity against Gram-positive and Gram-negative bacteria, was purified from the mesoglea of a scyphoid jellyfish Aurelia aurita by preparative gel electrophoresis and RP-HPLC. Molecular mass (4296.95 Da) and complete amino acid sequence of aurelin (AACSDRAHGHICESFKSFCKDSGRNGVKLRANCKKTCGLC) were determined.

Purification and primary structure of two isoforms of arenicin, a novel antimicrobial peptide from marine polychaeta Arenicola marina.

Two novel 21-residue antimicrobial peptides, arenicin-1 and arenicin-2, exhibiting activity against Gram-positive and Gram-negative bacteria and fungi, were purified from coelomocytes of marine polychaeta Arenicola marina (lugworm) by preparative gel electrophoresis and RP-HPLC. Molecular masses (2758.3 and 2772.

Domain structure and ATP-induced conformational changes in Escherichia coli protease Lon revealed by limited proteolysis and autolysis.

Escherichia coli protease Lon (La) is an adenosine triphosphate (ATP)-regulated homo-oligomeric proteolytic complex responsible for the recognition and selective degradation of abnormal and unstable proteins. Each subunit of the protease Lon appears to consist of three functional domains: the C-terminal proteolytic containing a serine active site, the central displaying the ATPase activity, and the N-terminal with still obscure function. We have used limited proteolysis to probe the domain structure and nucleotide-induced conformational changes in the enzyme.