D- and Unnatural Amino Acid Substituted Antimicrobial Peptides With Improved Proteolytic Resistance and Their Proteolytic Degradation Characteristics

Frontiers in Microbiology

卷:11

Jianghua Xia²  Jianguang Lu³  Jun Xu³  Yanan Li³  Jie Ma⁴  Hongjiang Xu⁴  Jun Feng⁴ 

[1] D, Shanghai Duomirui Biotechnology Co., Ltd., Shanghai, China;

[2] Department of Drug Evaluation and Research, Chia Tai Tianqing Pharmaceutical Group Co., Ltd., Nanjing, China;

[3] Department of Peptide Drugs R&

[4] Key State Laboratory of Drug Innovation and Pharmaceutical Technology, China State Institute of Pharmaceutical Industry, Shanghai, China;

关键词: antimicrobial peptides;    D-amino acid;    unnatural amino acid;    stability;    antimicrobial activity;    toxicity;   

DOI  :  10.3389/fmicb.2020.563030

来源: DOAJ

【 摘 要 】

The transition of antimicrobial peptides (AMPs) from the laboratory to market has been severely hindered by their instability toward proteases in biological systems. In the present study, we synthesized derivatives of the cationic AMP Pep05 (KRLFKKLLKYLRKF) by substituting L-amino acid residues with D- and unnatural amino acids, such as D-lysine, D-arginine, L-2,4-diaminobutanoic acid (Dab), L-2,3-diaminopropionic acid (Dap), L-homoarginine, 4-aminobutanoic acid (Aib), and L-thienylalanine, and evaluated their antimicrobial activities, toxicities, and stabilities toward trypsin, plasma proteases, and secreted bacterial proteases. In addition to measuring changes in the concentration of the intact peptides, LC-MS was used to identify the degradation products of the modified AMPs in the presence of trypsin and plasma proteases to determine degradation pathways and examine whether the amino acid substitutions afforded improved proteolytic resistance. The results revealed that both D- and unnatural amino acids enhanced the stabilities of the peptides toward proteases. The derivative DP06, in which all of the L-lysine and L-arginine residues were replaced by D-amino acids, displayed remarkable stability and mild toxicity in vitro but only slight activity and severe toxicity in vivo, indicating a significant difference between the in vivo and in vitro results. Unexpectedly, we found that the incorporation of a single Aib residue at the N-terminus of compound UP09 afforded remarkably enhanced plasma stability and improved activity in vivo. Hence, this derivative may represent a candidate AMP for further optimization, providing a new strategy for the design of novel AMPs with improved bioavailability.

【 授权许可】

Unknown