Poster Presentation 10th Australian Peptide Conference 2013

Better activity of shorter cathelicidin-derived peptide ll-31 against Burkholderia pseudomallei  (#118)

Hongsing Nuttaya 1 2 3 , Phophetleb Onanong 1 2 3 , Patramanon Rina 1 2 3
  1. Department of Oral Diagnosis, Faculty of Dentistry, Khon Kaen University, Khon Kaen 40002, Thailand
  2. Protein and proteomics research group, Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, thailand
  3. Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Burkholderia pseudomallei (BP)is causative agent of melioidosis, a disease endemic in tropical area such as in Southeast Asia and Northern Australia. Previous reports showed that cathelicidin-derived peptides LL-37 and its truncated LL-31 could inhibit growth of BP and LL-31 showed better activity than LL-37. This study aimed to elucidate the mechanism of action that allow better killing activity of LL-31 when comparing to LL-37 on live BPand membrane model, LL-31 showed better killing activities on BP than LL-37. In LPS-binding assay, LL-31 exhibited 9 to 14% displacement of PMB-BY whereas LL-37 exhibited only 3 to 5%. For the membrane permeabilization study, LL-31 showed slightly stronger in both outer and inner membrane permeation than LL-37, as observed with NPN-uptake assay and SYTOX® green influx in both cases. In addition, testing membrane fluidity by change in TMA-DPH and DPH anisotropy, results of this study showed that LL-37 could induce a change in membrane fluidity more effective than that of LL-31 through observed change in TMA-DPH anisotropy and DPH anisotropy. The leakage activity of ANTS/DPX liposome induced by LL-37 and LL-37 were about 55% and 50%, respectively. The hydrophobicity (H) and hydrophobic moment (µH) of LL-31 were more than those of LL-37. Taken together, we demonstrate better activity of LL-31 was through its better permeabilizing ability due to more hydrophobic content.