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Rami M, Shafique M, Sarma SP. Structural, Functional, and Mutational Studies of a Potent Subtilisin Inhibitor from Budgett's Frog, Lepidobatrachus laevis. Biochemistry 2023; 62:2952-2969. [PMID: 37796763 DOI: 10.1021/acs.biochem.3c00252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Subtilases play a significant role in microbial pathogen infections by degrading the host proteins. Subtilisin inhibitors are crucial in fighting against these harmful microorganisms. LL-TIL, from skin secretions of Lepidobatrachus laevis, is a cysteine-rich peptide belonging to the I8 family of inhibitors. Protease inhibitory assays demonstrated that LL-TIL acts as a slow-tight binding inhibitor of subtilisin Carlsberg and proteinase K with inhibition constants of 91 pM and 2.4 nM, respectively. The solution structures of LL-TIL and a mutant peptide reveal that they adopt a typical TIL-type fold with a canonical conformation of a reactive site loop (RSL). The structure of the LL-TIL-subtilisin complex and molecular dynamics (MD) simulations provided an in-depth view of the structural basis of inhibition. NMR relaxation data and molecular dynamics simulations indicated a rigid conformation of RSL, which does not alter significantly upon subtilisin binding. The energy calculation for subtilisin inhibition predicted Ile31 as the highest contributor to the binding energy, which was confirmed experimentally by site-directed mutagenesis. A chimeric mutant of LL-TIL broadened the inhibitory profile and attenuated subtilisin inhibition by 2 orders of magnitude. These results provide a template to engineer more specific and potent TIL-type subtilisin inhibitors.
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Affiliation(s)
- Mihir Rami
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Mohd Shafique
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Siddhartha P Sarma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Loy CA, Muli CS, Ali EMH, Xie D, Ahmed MH, Beth Post C, Trader DJ. Discovery of a non-covalent ligand for Rpn-13, a therapeutic target for hematological cancers. Bioorg Med Chem Lett 2023; 95:129485. [PMID: 37714498 PMCID: PMC10639113 DOI: 10.1016/j.bmcl.2023.129485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023]
Abstract
The ubiquitin-proteasome system serves as the major proteolytic degradation pathway in eukaryotic cells. Many inhibitors that covalently bind to the proteasome's active sites have been developed for hematological cancers, but resistance can arise in patients. To overcome limitations of active-site proteasome inhibitors, we and others have focused on developing ligands that target subunits on the 19S regulatory particle (19S RP). One such 19S RP subunit, Rpn-13, is a ubiquitin receptor required for hematological cancers to rapidly degrade proteins to avoid apoptosis. Reported Rpn-13 inhibitors covalently bind to the Rpn-13's Pru domain and have been effective anti-hematological cancer agents. Here, we describe the discovery of TCL-1, a non-covalent binder to the Pru domain. Optimization of TCL-1's carboxylate group to an ester increases its cytotoxicity in hematological cancer cell lines. Altogether, our data provides a new scaffold for future medicinal chemistry optimization to target Rpn-13 therapeutically.
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Affiliation(s)
- Cody A Loy
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States
| | - Christine S Muli
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States
| | - Eslam M H Ali
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States
| | - Dan Xie
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States
| | | | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States
| | - Darci J Trader
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 West Stadium Avenue, West Lafayette, IN 47907, United States.
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Březina V, Hanyková L, Velychkivska N, Hill JP, Labuta J. NMR lineshape analysis using analytical solutions of multi-state chemical exchange with applications to kinetics of host-guest systems. Sci Rep 2022; 12:17369. [PMID: 36253475 PMCID: PMC9576801 DOI: 10.1038/s41598-022-20136-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 09/08/2022] [Indexed: 01/10/2023] Open
Abstract
Nuclear magnetic resonance (NMR) lineshape analysis is a powerful tool for the study of chemical kinetics. Here we provide techniques for analysis of the relationship between experimentally observed spin kinetics (transitions between different environments [Formula: see text]) and corresponding chemical kinetics (transitions between distinct chemical species; e.g., free host and complexed host molecule). The advantages of using analytical solutions for two-, three- or generally N-state exchange lineshapes (without J-coupling) over the widely used numerical calculation for NMR spectral fitting are presented. Several aspects of exchange kinetics including the generalization of coalescence conditions in two-state exchange, the possibility of multiple processes between two states, and differences between equilibrium and steady-state modes are discussed. 'Reduced equivalent schemes' are introduced for spin kinetics containing fast-exchanging states, effectively reducing the number of exchanging states. The theoretical results have been used to analyze a host-guest system containing an oxoporphyrinogen complexed with camphorsulfonic acid and several other literature examples, including isomerization, protein kinetics, or enzymatic reactions. The theoretical treatment and experimental examples present an expansion of the systematic approach to rigorous analyses of systems with rich chemical kinetics through NMR lineshape analysis.
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Affiliation(s)
- Václav Březina
- grid.21941.3f0000 0001 0789 6880International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan ,grid.4491.80000 0004 1937 116XFaculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Lenka Hanyková
- grid.4491.80000 0004 1937 116XFaculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
| | - Nadiia Velychkivska
- grid.21941.3f0000 0001 0789 6880International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan ,grid.418095.10000 0001 1015 3316Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic
| | - Jonathan P. Hill
- grid.21941.3f0000 0001 0789 6880International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan
| | - Jan Labuta
- grid.21941.3f0000 0001 0789 6880International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044 Japan
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Sakhrani VV, Ghosh RK, Hilario E, Weiss KL, Coates L, Mueller LJ. Toho-1 β-lactamase: backbone chemical shift assignments and changes in dynamics upon binding with avibactam. JOURNAL OF BIOMOLECULAR NMR 2021; 75:303-318. [PMID: 34218390 PMCID: PMC9122098 DOI: 10.1007/s10858-021-00375-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 06/23/2021] [Indexed: 06/13/2023]
Abstract
Backbone chemical shift assignments for the Toho-1 β-lactamase (263 amino acids, 28.9 kDa) are reported based on triple resonance solution-state NMR experiments performed on a uniformly 2H,13C,15N-labeled sample. These assignments allow for subsequent site-specific characterization at the chemical, structural, and dynamical levels. At the chemical level, titration with the non-β-lactam β-lactamase inhibitor avibactam is found to give chemical shift perturbations indicative of tight covalent binding that allow for mapping of the inhibitor binding site. At the structural level, protein secondary structure is predicted based on the backbone chemical shifts and protein residue sequence using TALOS-N and found to agree well with structural characterization from X-ray crystallography. At the dynamical level, model-free analysis of 15N relaxation data at a single field of 16.4 T reveals well-ordered structures for the ligand-free and avibactam-bound enzymes with generalized order parameters of ~ 0.85. Complementary relaxation dispersion experiments indicate that there is an escalation in motions on the millisecond timescale in the vicinity of the active site upon substrate binding. The combination of high rigidity on short timescales and active site flexibility on longer timescales is consistent with hypotheses for achieving both high catalytic efficiency and broad substrate specificity: the induced active site dynamics allows variously sized substrates to be accommodated and increases the probability that the optimal conformation for catalysis will be sampled.
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Affiliation(s)
- Varun V Sakhrani
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Rittik K Ghosh
- Department of Biochemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Eduardo Hilario
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA
| | - Kevin L Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA
| | - Leighton Coates
- Second Target Station, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN, 37831, USA.
| | - Leonard J Mueller
- Department of Chemistry, University of California Riverside, Riverside, CA, 92521, USA.
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