Mechanism of action of thalassospiramides, a new class of calpain inhibitors.
Thalassospiramides comprise a large family of lipopeptide natural products produced by Thalassospira and Tistrella marine bacteria. Here we provide further evidence of their nanomolar inhibitory activity against the human calpain 1 protease. Analysis of structure-activity relationship data supported our hypothesis that the rigid 12-membered ring containing an α,β-unsaturated carbonyl moiety is the pharmacologically active functional group, in contrast to classic electrophilic "warheads" in known calpain inhibitors. Using a combination of chemical modifications, mass spectrometric techniques, site-directed mutagenesis, and molecular modeling, we show the covalent binding of thalassospiramide's α,β-unsaturated carbonyl moiety to the thiol group of calpain's catalytic Cys115 residue by a Michael 1,4-addition reaction. As nanomolar calpain inhibitors with promising selectivity and low toxicity from natural sources are rare, we consider thalassospiramides as promising drug leads.
KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Liang
L
Lu
Skaggs School of Pharmacy &Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92037, United States.
Michael J
MJ
Meehan
Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Shuo
S
Gu
Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Zhilong
Z
Chen
KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Weipeng
W
Zhang
KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Gen
G
Zhang
KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Lingli
L
Liu
Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Xuhui
X
Huang
1] Skaggs School of Pharmacy &Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92037, United States [2] Department of Pharmacology, University of California at San Diego, La Jolla, California 92037, United States [3] Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92037, United States.
Pieter C
PC
Dorrestein
1] KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China [2] School of Life Science, Shenzhen University, Nanhai Ave 3688, Shenzhen, Guangdong Province, 518060, China.
Ying
Y
Xu
1] Skaggs School of Pharmacy &Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92037, United States [2] Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92037, United States.
Bradley S
BS
Moore
KAUST Global Collaborative Research, Division of Life Science, School of Science, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
Pei-Yuan
PY
Qian
D002154:Calpain / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D006023:Glycoproteins / Q000737:chemistry* / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D008968:Molecular Conformation; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000494:pharmacology*; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared
D006023:Glycoproteins; D010456:Peptides, Cyclic; C039304:calpain inhibitors; D002154:Calpain