Flavonoid-mediated inhibition of SARS coronavirus 3C-like protease expressed in Pichia pastoris

  • Biotechnol Lett. 2012 May;34(5):831-8. doi: 10.1007/s10529-011-0845-8.
Thi Thanh Hanh Nguyen  1 ,  Hye-Jin Woo ,  Hee-Kyoung Kang ,  Van Dao Nguyen ,  Young-Min Kim ,  Do-Won Kim ,  Sul-Ah Ahn ,  Yongmei Xia ,  Doman Kim
Affiliations
  • 1. School of Biological Sciences and Technology and the Research Institute for Catalysis, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 500-757, Republic of Korea.
PMID: 22350287 DOI: 10.1007/s10529-011-0845-8
Abstract

The 3C-like protease (3CL(pro)) of severe acute respiratory syndrome associated coronavirus (SARS-CoV) is vital for SARS-CoV replication and is a promising drug target. Recombinant 3CL(pro) was expressed in Pichia pastoris GS115 as a 42 kDa protein that displayed a K ( m ) of 15 ± 2 μM with Dabcyl-KTSAVLQSGFRKME-Edans as substrate. Purified 3CL(pro) was used for inhibition and kinetic assays with seven flavonoid compounds. The IC(50) of six flavonoid compounds were 47-381 μM. Quercetin, epigallocatechin gallate and gallocatechin gallate (GCG) displayed good inhibition toward 3CL(pro) with IC(50) values of 73, 73 and 47 μM, respectively. GCG showed a competitive inhibition pattern with K ( i ) value of 25 ± 1.7 μM. In molecular docking experiments, GCG displayed a binding energy of -14 kcal mol(-1) to the active site of 3CL(pro) and the galloyl moiety at 3-OH position was required for 3CL(pro) inhibition activity.

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