title: The stereochemical effect of SMAP-29 and SMAP-18 on bacterial selectivity, membrane interaction and anti-inflammatory activity.
abstract: Sheep myeloid antimicrobial peptide-29 (SMAP-29) is a cathelicidin-related antimicrobial peptide derived from sheep myeloid cells. In order to investigate the effects of L-to-D-amino acid substitution in SMAP-29 on bacterial selectivity, membrane interaction and anti-inflammatory activity, we synthesized its two D-enantiomeric peptides (SMAP-29-E1 and SMAP-29-E2 containing D-Ile and D-allo-Ile, respectively) and two diastereomeric peptides (SMAP-29-D1 and SMAP-29-D2). Additionally, in order to address the effect of L-to-D-amino acid substitution in the N-terminal helical peptide of SMAP-29 (named SMAP-18) on antimicrobial activity, we synthesized its two D-enantiomeric peptides (SMAP-18-E1 and SMAP-18-E2), which are composed of D-amino acids entirely. L-to-D-amino acid substitution in membrane-targeting AMP, SMAP-29 did not affect its antimicrobial activity. However, D-allo-Ile containing-SMAP-29-E2 and SMAP-29-D2 exhibited less hemolytic activity compared to D-Ile containing-SMAP-29-E1 and SMAP-29-D1, respectively. L-to-D-amino acid substitution in intracellular targeting-AMPs, SMAP-18 and buforin-2 improved antimicrobial activity by 2- to eightfold. The improved antimicrobial activity of the D-isomers of SMAP-18 and buforin-2 seems to be due to the stability against proteases inside bacterial cells. Membrane depolarization and dye leakage suggested that the membrane-disruptive mode of SMAP-29-D1 and SMAP-29-D2 is different from that of SMAP-29, SMAP-29-E1, and SMAP-29-E2. L-to-D-amino acid substitution in SMAP-29 improved anti-inflammatory activity in LPS-stimulated RAW 264.7 cells. In summary, we propose here that D-allo-Ile substitution is a more powerful strategy for increasing bacterial selectivity than D-Ile substitution in the design of D-enantiomeric and diastereomeric AMPs. SMAP-29-D1, and SMAP-29-D2 with improved bacterial selectivity and anti-inflammatory activity can serve as promising candidates for the development of anti-inflammatory and antimicrobial agents.
authors.affiliation: Department of Medical Science, Graduate School, Chosun University, Gwangju, 501-759, Republic of Korea.
authors.forename: Binu
authors.initials: B
authors.lastname: Jacob
authors.affiliation: Department of Medical Science, Graduate School, Chosun University, Gwangju, 501-759, Republic of Korea.
authors.forename: Ganesan
authors.initials: G
authors.lastname: Rajasekaran
authors.affiliation: Department of Medical Science, Graduate School, Chosun University, Gwangju, 501-759, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.affiliation: Department of Medical Science, Graduate School, Chosun University, Gwangju, 501-759, Republic of Korea.|Department of Cellular and Molecular Medicine, School of Medicine, Chosun University, Gwangju, 501-759, Republic of Korea.
authors.forename: Il-Seon
authors.initials: IS
authors.lastname: Park
authors.affiliation: Division of Magnetic Resonance, Korea Basic Science Institute, 804-1 Yangchung-ri, Ochang, Chungbuk, 363-883, Republic of Korea. bangjk@kbsi.re.kr.
authors.forename: Jeong-Kyu
authors.initials: JK
authors.lastname: Bang
authors.affiliation: Department of Medical Science, Graduate School, Chosun University, Gwangju, 501-759, Republic of Korea. syshin@chosun.ac.kr.|Department of Cellular and Molecular Medicine, School of Medicine, Chosun University, Gwangju, 501-759, Republic of Korea. syshin@chosun.ac.kr.
authors.forename: Song Yub
authors.initials: SY
authors.lastname: Shin
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D000893:Anti-Inflammatory Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001798:Blood Proteins / Q000737:chemistry* / Q000494:pharmacology*; D054804:Cathelicidins / Q000737:chemistry* / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects*; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008826:Microbial Sensitivity Tests; D000067996:RAW 264.7 Cells; D012756:Sheep; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D000893:Anti-Inflammatory Agents; D001798:Blood Proteins; D054804:Cathelicidins; C403305:SMAP29 protein, Ovis aries
keywords: Anti-inflammatory activity; Bacterial selectivity; L-to-D-amino acid substitution; Protease stability; SMAP-29/SMAP-18