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Harris WT, Altieri I, Gieck I, Johnson RJ. A conserved but structurally divergent loop in acyl protein thioesterase 1 regulates its catalytic activity, ligand binding, and folded stability. Proteins 2024; 92:693-704. [PMID: 38179877 DOI: 10.1002/prot.26661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/06/2024]
Abstract
Human acyl protein thioesterases (APTs) catalyze the depalmitoylation of S-acylated proteins attached to the plasma membrane, facilitating reversible cycles of membrane anchoring and detachment. We previously showed that a bacterial APT homologue, FTT258 from the gram-negative pathogen Francisella tularensis, exists in equilibrium between a closed and open state based on the structural dynamics of a flexible loop overlapping its active site. Although the structural dynamics of this loop are not conserved in human APTs, the amino acid sequence of this loop is highly conserved, indicating essential but divergent functions for this loop in human APTs. Herein, we investigated the role of this loop in regulating the catalytic activity, ligand binding, and protein folding of human APT1, a depalmitoylase connected with cancer, immune, and neurological signaling. Using a combination of substitutional analysis with kinetic, structural, and biophysical characterization, we show that even in its divergent structural location in human APT1 that this loop still regulates the catalytic activity of APT1 through contributions to ligand binding and substrate positioning. We confirmed previously known roles for multiple residues (Phe72 and Ile74) in substrate binding and catalysis while adding new roles in substrate selectivity (Pro69), in catalytic stabilization (Asp73 and Ile75), and in transitioning between the membrane binding β-tongue and substrate-binding loops (Trp71). Even conservative substitution of this tryptophan (Trp71) fulcrum led to complete loss of catalytic activity, a 13°C decrease in total protein stability, and drastic drops in ligand affinity, indicating that the combination of the size, shape, and aromaticity of Trp71 are essential to the proper structure of APT1. Mixing buried hydrophobic surface area with contributions to an exposed secondary surface pocket, Trp71 represents a previously unidentified class of essential tryptophans within α/β hydrolase structure and a potential allosteric binding site within human APTs.
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Affiliation(s)
- William Trey Harris
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA
| | - Isabelle Altieri
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA
| | - Isabella Gieck
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA
| | - R Jeremy Johnson
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, USA
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2
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Schemenauer D, Pool EH, Raynor SN, Ruiz GP, Goehring LM, Koelper AJ, Wilson MA, Durand AJ, Kourtoglou EC, Larsen EM, Lavis LD, Esteb JJ, Hoops GC, Johnson RJ. Sequence and Structural Motifs Controlling the Broad Substrate Specificity of the Mycobacterial Hormone-Sensitive Lipase LipN. ACS OMEGA 2023; 8:13252-13264. [PMID: 37065048 PMCID: PMC10099132 DOI: 10.1021/acsomega.3c00534] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/24/2023] [Indexed: 06/19/2023]
Abstract
Mycobacterium tuberculosis has a complex life cycle transitioning between active and dormant growth states depending on environmental conditions. LipN (Rv2970c) is a conserved mycobacterial serine hydrolase with regulated catalytic activity at the interface between active and dormant growth conditions. LipN also catalyzes the xenobiotic degradation of a tertiary ester substrate and contains multiple conserved motifs connected with the ability to catalyze the hydrolysis of difficult tertiary ester substrates. Herein, we expanded a library of fluorogenic ester substrates to include more tertiary and constrained esters and screened 33 fluorogenic substrates for activation by LipN, identifying its unique substrate signature. LipN preferred short, unbranched ester substrates, but had its second highest activity against a heteroaromatic five-membered oxazole ester. Oxazole esters are present in multiple mycobacterial serine hydrolase inhibitors but have not been tested widely as ester substrates. Combined structural modeling, kinetic measurements, and substitutional analysis of LipN showcased a fairly rigid binding pocket preorganized for catalysis of short ester substrates. Substitution of diverse amino acids across the binding pocket significantly impacted the folded stability and catalytic activity of LipN with two conserved motifs (HGGGW and GDSAG) playing interconnected, multidimensional roles in regulating its substrate specificity. Together this detailed substrate specificity profile of LipN illustrates the complex interplay between structure and function in mycobacterial hormone-sensitive lipase homologues and indicates oxazole esters as promising inhibitor and substrate scaffolds for mycobacterial hydrolases.
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Affiliation(s)
- Daniel
E. Schemenauer
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Emily H. Pool
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Stephanie N. Raynor
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Gabriela P. Ruiz
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Leah M. Goehring
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Andrew J. Koelper
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Madeleine A. Wilson
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Anthony J. Durand
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Elexi C. Kourtoglou
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Erik M. Larsen
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Luke D. Lavis
- Howard
Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia 20147, United States
| | - John J. Esteb
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - Geoffrey C. Hoops
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
| | - R. Jeremy Johnson
- Department
of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208, United States
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Sowlati-Hashjin S, Gandhi A, Garton M. Dawn of a New Era for Membrane Protein Design. BIODESIGN RESEARCH 2022; 2022:9791435. [PMID: 37850134 PMCID: PMC10521746 DOI: 10.34133/2022/9791435] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/20/2022] [Indexed: 10/19/2023] Open
Abstract
A major advancement has recently occurred in the ability to predict protein secondary structure from sequence using artificial neural networks. This new accessibility to high-quality predicted structures provides a big opportunity for the protein design community. It is particularly welcome for membrane protein design, where the scarcity of solved structures has been a major limitation of the field for decades. Here, we review the work done to date on the membrane protein design and set out established and emerging tools that can be used to most effectively exploit this new access to structures.
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Affiliation(s)
- Shahin Sowlati-Hashjin
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada, M5S 3E2
| | - Aanshi Gandhi
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada, M5S 3E2
| | - Michael Garton
- Institute of Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON, Canada, M5S 3E2
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Bun JS, Slack MD, Schemenauer DE, Johnson RJ. Comparative analysis of the human serine hydrolase OVCA2 to the model serine hydrolase homolog FSH1 from S. cerevisiae. PLoS One 2020; 15:e0230166. [PMID: 32182256 PMCID: PMC7077851 DOI: 10.1371/journal.pone.0230166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 02/20/2020] [Indexed: 11/22/2022] Open
Abstract
Over 100 metabolic serine hydrolases are present in humans with confirmed functions in metabolism, immune response, and neurotransmission. Among potentially clinically-relevant but uncharacterized human serine hydrolases is OVCA2, a serine hydrolase that has been linked with a variety of cancer-related processes. Herein, we developed a heterologous expression system for OVCA2 and determined the comprehensive substrate specificity of OVCA2 against two ester substrate libraries. Based on this analysis, OVCA2 was confirmed as a serine hydrolase with a strong preference for long-chain alkyl ester substrates (>10-carbons) and high selectivity against a variety of short, branched, and substituted esters. Substitutional analysis was used to identify the catalytic residues of OVCA2 with a Ser117-His206-Asp179 classic catalytic triad. Comparison of the substrate specificity of OVCA2 to the model homologue FSH1 from Saccharomyces cerevisiae illustrated the tighter substrate selectivity of OVCA2, but their overlapping substrate preference for extended straight-chain alkyl esters. Conformation of the overlapping biochemical properties of OVCA2 and FSH1 was used to model structural information about OVCA2. Together our analysis provides detailed substrate specificity information about a previously, uncharacterized human serine hydrolase and begins to define the biological properties of OVCA2.
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Affiliation(s)
- Jessica S. Bun
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - Michael D. Slack
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - Daniel E. Schemenauer
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
| | - R. Jeremy Johnson
- Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana, United States of America
- * E-mail:
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Fang X, Zheng Y, Duan Y, Liu Y, Zhong W. Recent Advances in Design of Fluorescence-Based Assays for High-Throughput Screening. Anal Chem 2019; 91:482-504. [PMID: 30481456 PMCID: PMC7262998 DOI: 10.1021/acs.analchem.8b05303] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xiaoni Fang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yongzan Zheng
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yaokai Duan
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yang Liu
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, United States
| | - Wenwan Zhong
- Department of Chemistry, University of California, Riverside, California 92521, United States
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, United States
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White A, Koelper A, Russell A, Larsen EM, Kim C, Lavis LD, Hoops GC, Johnson RJ. Fluorogenic structure activity library pinpoints molecular variations in substrate specificity of structurally homologous esterases. J Biol Chem 2018; 293:13851-13862. [PMID: 30006352 DOI: 10.1074/jbc.ra118.003972] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/11/2018] [Indexed: 01/08/2023] Open
Abstract
Cellular esterases catalyze many essential biological functions by performing hydrolysis reactions on diverse substrates. The promiscuity of esterases complicates assignment of their substrate preferences and biological functions. To identify universal factors controlling esterase substrate recognition, we designed a 32-member structure-activity relationship (SAR) library of fluorogenic ester substrates and used this library to systematically interrogate esterase preference for chain length, branching patterns, and polarity to differentiate common classes of esterase substrates. Two structurally homologous bacterial esterases were screened against this library, refining their previously broad overlapping substrate specificity. Vibrio cholerae esterase ybfF displayed a preference for γ-position thioethers and ethers, whereas Rv0045c from Mycobacterium tuberculosis displayed a preference for branched substrates with and without thioethers. We determined that this substrate differentiation was partially controlled by individual substrate selectivity residues Tyr-119 in ybfF and His-187 in Rv0045c; reciprocal substitution of these residues shifted each esterase's substrate preference. This work demonstrates that the selectivity of esterases is tuned based on transition state stabilization, identifies thioethers as an underutilized functional group for esterase substrates, and provides a rapid method for differentiating structural isozymes. This SAR library could have multifaceted future applications, including in vivo imaging, biocatalyst screening, molecular fingerprinting, and inhibitor design.
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Affiliation(s)
- Alex White
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
| | - Andrew Koelper
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
| | - Arielle Russell
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
| | - Erik M Larsen
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
| | - Charles Kim
- the Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia 20147-2439
| | - Luke D Lavis
- the Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, Virginia 20147-2439
| | - Geoffrey C Hoops
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
| | - R Jeremy Johnson
- From the Department of Chemistry and Biochemistry, Butler University, Indianapolis, Indiana 46208-3443 and
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