PDBsum entry 4tsx

DNA binding protein

PDB id: 4tsx

Contents

Protein chain

145 a.a.

Ligands

LF0

SO4 ×2

Waters ×56

PDB id:

4tsx

Name:

DNA binding protein

Title:

HIV-1 integrase catalytic core domain mutant complexed with allosteric inhibitor

Structure:

Integrase. Chain: a. Fragment: catalytical core domain, unp residues 50-212. Engineered: yes. Mutation: yes

Source:

Human immunodeficiency virus 1. Organism_taxid: 11676. Gene: pol. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.94Å R-factor: 0.193 R-free: 0.221

Authors:

L.Feng,M.Kvaratskhelia

Key ref:

A.Slaughter et al. (2014). The mechanism of H171T resistance reveals the importance of Nδ-protonated His171 for the binding of allosteric inhibitor BI-D to HIV-1 integrase. Retrovirology, 11, 100. PubMed id: 25421939 DOI: 10.1186/s12977-014-0100-1

Date:

19-Jun-14 Release date: 17-Dec-14

Protein chain

F2WR39  (F2WR39_HV1) -  Integrase (Fragment) from Human immunodeficiency virus type 1

Seq: 288 a.a.

Struc: 145 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

DOI no: 10.1186/s12977-014-0100-1

Retrovirology 11:100 (2014)

PubMed id: 25421939

The mechanism of H171T resistance reveals the importance of Nδ-protonated His171 for the binding of allosteric inhibitor BI-D to HIV-1 integrase.

A.Slaughter, K.A.Jurado, N.Deng, L.Feng, J.J.Kessl, N.Shkriabai, R.C.Larue, H.J.Fadel, P.A.Patel, N.Jena, J.R.Fuchs, E.Poeschla, R.M.Levy, A.Engelman, M.Kvaratskhelia.

ABSTRACT

BackgroundAllosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are an important new class of anti-HIV-1 agents. ALLINIs bind at the IN catalytic core domain (CCD) dimer interface occupying the principal binding pocket of its cellular cofactor LEDGF/p75. Consequently, ALLINIs inhibit HIV-1 IN interaction with LEDGF/p75 as well as promote aberrant IN multimerization. Selection of viral strains emerging under the inhibitor pressure has revealed mutations at the IN dimer interface near the inhibitor binding site.ResultsWe have investigated the effects of one of the most prevalent substitutions, H171T IN, selected under increasing pressure of ALLINI BI-D. Virus containing the H171T IN substitution exhibited an ~68-fold resistance to BI-D treatment in infected cells. These results correlated with ~84-fold reduced affinity for BI-D binding to recombinant H171T IN CCD protein compared to its wild type (WT) counterpart. However, the H171T IN substitution only modestly affected IN-LEDGF/p75 binding and allowed HIV-1 containing this substitution to replicate at near WT levels. The x-ray crystal structures of BI-D binding to WT and H171T IN CCD dimers coupled with binding free energy calculations revealed the importance of the N¿- protonated imidazole group of His171 for hydrogen bonding to the BI-D tert-butoxy ether oxygen and establishing electrostatic interactions with the inhibitor carboxylic acid, whereas these interactions were compromised upon substitution to Thr171.ConclusionsOur findings reveal a distinct mechanism of resistance for the H171T IN mutation to ALLINI BI-D and indicate a previously undescribed role of the His171 side chain for binding the inhibitor.