1
|
Kinshuk S, Li L, Meckes B, Chan CTY. Sequence-Based Protein Design: A Review of Using Statistical Models to Characterize Coevolutionary Traits for Developing Hybrid Proteins as Genetic Sensors. Int J Mol Sci 2024; 25:8320. [PMID: 39125888 PMCID: PMC11312098 DOI: 10.3390/ijms25158320] [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: 07/02/2024] [Revised: 07/23/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024] Open
Abstract
Statistical analyses of homologous protein sequences can identify amino acid residue positions that co-evolve to generate family members with different properties. Based on the hypothesis that the coevolution of residue positions is necessary for maintaining protein structure, coevolutionary traits revealed by statistical models provide insight into residue-residue interactions that are important for understanding protein mechanisms at the molecular level. With the rapid expansion of genome sequencing databases that facilitate statistical analyses, this sequence-based approach has been used to study a broad range of protein families. An emerging application of this approach is to design hybrid transcriptional regulators as modular genetic sensors for novel wiring between input signals and genetic elements to control outputs. Among many allosterically regulated regulator families, the members contain structurally conserved and functionally independent protein domains, including a DNA-binding module (DBM) for interacting with a specific genetic element and a ligand-binding module (LBM) for sensing an input signal. By hybridizing a DBM and an LBM from two different family members, a hybrid regulator can be created with a new combination of signal-detection and DNA-recognition properties not present in natural systems. In this review, we present recent advances in the development of hybrid regulators and their applications in cellular engineering, especially focusing on the use of statistical analyses for characterizing DBM-LBM interactions and hybrid regulator design. Based on these studies, we then discuss the current limitations and potential directions for enhancing the impact of this sequence-based design approach.
Collapse
Affiliation(s)
- Sahaj Kinshuk
- Department of Biomedical Engineering, College of Engineering, University of North Texas, 3940 N Elm Street, Denton, TX 76207, USA; (S.K.); (L.L.); (B.M.)
| | - Lin Li
- Department of Biomedical Engineering, College of Engineering, University of North Texas, 3940 N Elm Street, Denton, TX 76207, USA; (S.K.); (L.L.); (B.M.)
| | - Brian Meckes
- Department of Biomedical Engineering, College of Engineering, University of North Texas, 3940 N Elm Street, Denton, TX 76207, USA; (S.K.); (L.L.); (B.M.)
- BioDiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203, USA
| | - Clement T. Y. Chan
- Department of Biomedical Engineering, College of Engineering, University of North Texas, 3940 N Elm Street, Denton, TX 76207, USA; (S.K.); (L.L.); (B.M.)
- BioDiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203, USA
| |
Collapse
|
2
|
Goldman AL, Fulk EM, Momper LM, Heider C, Mulligan J, Osburn M, Masiello CA, Silberg JJ. Microbial sensor variation across biogeochemical conditions in the terrestrial deep subsurface. mSystems 2024; 9:e0096623. [PMID: 38059636 PMCID: PMC10805038 DOI: 10.1128/msystems.00966-23] [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: 09/15/2023] [Accepted: 11/08/2023] [Indexed: 12/08/2023] Open
Abstract
Microbes can be found in abundance many kilometers underground. While microbial metabolic capabilities have been examined across different geochemical settings, it remains unclear how changes in subsurface niches affect microbial needs to sense and respond to their environment. To address this question, we examined how microbial extracellular sensor systems vary with environmental conditions across metagenomes at different Deep Mine Microbial Observatory (DeMMO) subsurface sites. Because two-component systems (TCSs) directly sense extracellular conditions and convert this information into intracellular biochemical responses, we expected that this sensor family would vary across isolated oligotrophic subterranean environments that differ in abiotic and biotic conditions. TCSs were found at all six subsurface sites, the service water control, and the surface site, with an average of 0.88 sensor histidine kinases (HKs) per 100 genes across all sites. Abundance was greater in subsurface fracture fluids compared with surface-derived fluids, and candidate phyla radiation (CPR) bacteria presented the lowest HK frequencies. Measures of microbial diversity, such as the Shannon diversity index, revealed that HK abundance is inversely correlated with microbial diversity (r2 = 0.81). Among the geochemical parameters measured, HK frequency correlated most strongly with variance in dissolved organic carbon (r2 = 0.82). Taken together, these results implicate the abiotic and biotic properties of an ecological niche as drivers of sensor needs, and they suggest that microbes in environments with large fluctuations in organic nutrients (e.g., lacustrine, terrestrial, and coastal ecosystems) may require greater TCS diversity than ecosystems with low nutrients (e.g., open ocean).IMPORTANCEThe ability to detect extracellular environmental conditions is a fundamental property of all life forms. Because microbial two-component sensor systems convert information about extracellular conditions into biochemical information that controls their behaviors, we evaluated how two-component sensor systems evolved within the deep Earth across multiple sites where abiotic and biotic properties vary. We show that these sensor systems remain abundant in microbial consortia at all subterranean sampling sites and observe correlations between sensor system abundances and abiotic (dissolved organic carbon variation) and biotic (consortia diversity) properties. These results suggest that multiple environmental properties may drive sensor protein evolution and highlight the need for further studies of metagenomic and geochemical data in parallel to understand the drivers of microbial sensor evolution.
Collapse
Affiliation(s)
| | - Emily M. Fulk
- Systems, Synthetic, and Physical Biology Graduate Program, Rice University, Houston, Texas, USA
| | - Lily M. Momper
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - Clinton Heider
- Rice University, Center for Research Computing, Houston, Texas, USA
| | - John Mulligan
- Rice University, Center for Research Computing, Houston, Texas, USA
| | - Magdalena Osburn
- Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois, USA
| | - Caroline A. Masiello
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Earth, Environmental and Planetary Sciences, Rice University, Houston, Texas, USA
- Department of Chemistry, Rice University, Houston, Texas, USA
| | - Jonathan J. Silberg
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, USA
| |
Collapse
|
3
|
Hersey AN, Kay VE, Lee S, Realff MJ, Wilson CJ. Engineering allosteric transcription factors guided by the LacI topology. Cell Syst 2023; 14:645-655. [PMID: 37591203 DOI: 10.1016/j.cels.2023.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 02/26/2023] [Accepted: 04/26/2023] [Indexed: 08/19/2023]
Abstract
Allosteric transcription factors (aTFs) are used in a myriad of processes throughout biology and biotechnology. aTFs have served as the workhorses for developments in synthetic biology, fundamental research, and protein manufacturing. One of the most utilized TFs is the lactose repressor (LacI). In addition to being an exceptional tool for gene regulation, LacI has also served as an outstanding model system for understanding allosteric communication. In this perspective, we will use the LacI TF as the principal exemplar for engineering alternate functions related to allostery-i.e., alternate protein DNA interactions, alternate protein-ligand interactions, and alternate phenotypic mechanisms. In addition, we will summarize the design rules and heuristics for each design goal and demonstrate how the resulting design rules and heuristics can be extrapolated to engineer other aTFs with a similar topology-i.e., from the broader LacI/GalR family of TFs.
Collapse
Affiliation(s)
- Ashley N Hersey
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Valerie E Kay
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Sumin Lee
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Matthew J Realff
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA
| | - Corey J Wilson
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, Atlanta, GA, USA.
| |
Collapse
|
4
|
Chen J, Vishweshwaraiah YL, Dokholyan NV. Design and engineering of allosteric communications in proteins. Curr Opin Struct Biol 2022; 73:102334. [PMID: 35180676 PMCID: PMC8957532 DOI: 10.1016/j.sbi.2022.102334] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/30/2021] [Accepted: 01/05/2022] [Indexed: 01/26/2023]
Abstract
Allostery in proteins plays an important role in regulating protein activities and influencing many biological processes such as gene expression, enzyme catalysis, and cell signaling. The process of allostery takes place when a signal detected at a site on a protein is transmitted via a mechanical pathway to a functional site and, thus, influences its activity. The pathway of allosteric communication consists of amino acids that form a network with covalent and non-covalent bonds. By mutating residues in this allosteric network, protein engineers have successfully established novel allosteric pathways to achieve desired properties in the target protein. In this review, we highlight the most recent and state-of-the-art techniques for allosteric communication engineering. We also discuss the challenges that need to be overcome and future directions for engineering protein allostery.
Collapse
Affiliation(s)
- Jiaxing Chen
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, 17033-0850, USA. https://twitter.com/JiaxingChen18
| | - Yashavantha L Vishweshwaraiah
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, 17033-0850, USA. https://twitter.com/IAmYashHegde
| | - Nikolay V Dokholyan
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, 17033-0850, USA; Department of Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA, 17033-0850, USA; Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA; Department of Biomedical Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
| |
Collapse
|
5
|
Design of a methotrexate-controlled chemical dimerization system and its use in bio-electronic devices. Nat Commun 2021; 12:7137. [PMID: 34880210 PMCID: PMC8654847 DOI: 10.1038/s41467-021-27184-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 11/03/2021] [Indexed: 11/08/2022] Open
Abstract
Natural evolution produced polypeptides that selectively recognize chemical entities and their polymers, ranging from ions to proteins and nucleic acids. Such selective interactions serve as entry points to biological signaling and metabolic pathways. The ability to engineer artificial versions of such entry points is a key goal of synthetic biology, bioengineering and bioelectronics. We set out to map the optimal strategy for developing artificial small molecule:protein complexes that function as chemically induced dimerization (CID) systems. Using several starting points, we evolved CID systems controlled by a therapeutic drug methotrexate. Biophysical and structural analysis of methotrexate-controlled CID system reveals the critical role played by drug-induced conformational change in ligand-controlled protein complex assembly. We demonstrate utility of the developed CID by constructing electrochemical biosensors of methotrexate that enable quantification of methotrexate in human serum. Furthermore, using the methotrexate and functionally related biosensor of rapamycin we developed a multiplexed bioelectronic system that can perform repeated measurements of multiple analytes. The presented results open the door for construction of genetically encoded signaling systems for use in bioelectronics and diagnostics, as well as metabolic and signaling network engineering.
Collapse
|
6
|
Biological signal processing filters via engineering allosteric transcription factors. Proc Natl Acad Sci U S A 2021; 118:2111450118. [PMID: 34772815 PMCID: PMC8609624 DOI: 10.1073/pnas.2111450118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 11/18/2022] Open
Abstract
As the size and complexity of genetic circuits increases, scientists and engineers need to find solutions to rapidly optimize flux and reduce the metabolic burden imposed on chassis cells. In this study, we report synthetic biology tools that imbue chassis cells with advanced signal processing functions akin to electrical devices commonly used in wireless transmitters and receivers (i.e., biological BANDPASS and BANDSTOP devices) that can simultaneously reduce metabolic burden. Moreover, this study presents a set of granular and more complete design rules for engineering allosteric transcription factors in the broader LacI/GalR topology. In addition, this study has improved our fundamental understanding of the plasticity and continuum of allosteric communication from the binding pocket to the protein–DNA interaction. Signal processing is critical to a myriad of biological phenomena (natural and engineered) that involve gene regulation. Biological signal processing can be achieved by way of allosteric transcription factors. In canonical regulatory systems (e.g., the lactose repressor), an INPUT signal results in the induction of a given transcription factor and objectively switches gene expression from an OFF state to an ON state. In such biological systems, to revert the gene expression back to the OFF state requires the aggressive dilution of the input signal, which can take 1 or more d to achieve in a typical biotic system. In this study, we present a class of engineered allosteric transcription factors capable of processing two-signal INPUTS, such that a sequence of INPUTS can rapidly transition gene expression between alternating OFF and ON states. Here, we present two fundamental biological signal processing filters, BANDPASS and BANDSTOP, that are regulated by D-fucose and isopropyl-β-D-1-thiogalactopyranoside. BANDPASS signal processing filters facilitate OFF–ON–OFF gene regulation. Whereas, BANDSTOP filters facilitate the antithetical gene regulation, ON–OFF–ON. Engineered signal processing filters can be directed to seven orthogonal promoters via adaptive modular DNA binding design. This collection of signal processing filters can be used in collaboration with our established transcriptional programming structure. Kinetic studies show that our collection of signal processing filters can switch between states of gene expression within a few minutes with minimal metabolic burden—representing a paradigm shift in general gene regulation.
Collapse
|
7
|
Grasso EM, Majumdar A, Wrabl JO, Frueh DP, Hilser VJ. Conserved allosteric ensembles in disordered proteins using TROSY/anti-TROSY R 2-filtered spectroscopy. Biophys J 2021; 120:2498-2510. [PMID: 33901472 PMCID: PMC8390865 DOI: 10.1016/j.bpj.2021.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/11/2021] [Accepted: 04/16/2021] [Indexed: 11/22/2022] Open
Abstract
Defining the role of intrinsic disorder in proteins in the myriad of biological processes with which it is involved represents a significant goal in modern biophysics. Toward this end, NMR is uniquely suited for molecular studies of dynamic and disordered regions, but studying these regions in concert with their more structured domains and binding partners presents spectroscopic challenges. Here, we investigate the interactions between the structured and disordered regions of the human glucocorticoid receptor (GR). To do this, we developed an NMR strategy that relies on a novel relaxation filter for the simultaneous study of structured and unstructured regions. Using this approach, we conducted a comparative analysis of three translational isoforms of GR containing a folded DNA-binding domain (DBD) and two disordered regions that flank the DBD, one of which varies in size in the different isoforms. Notably, we were able to assign resonances that had previously been inaccessible because of the spectral complexity of the translational isoforms, which in turn allowed us to 1) identify a region of the structured DBD that undergoes significant changes in the local chemical environment in the presence of the disordered region and 2) determine differences in the conformational ensembles of the disordered regions of the translational isoforms. Furthermore, an ensemble-based thermodynamic analysis of the isoforms reveals conserved patterns of stability within the N-terminal domain of GR that persist despite low sequence conservation. These studies provide an avenue for further investigations of the mechanistic underpinnings of the functional relevance of the translational isoforms of GR while also providing a general NMR strategy for studying systems containing both structured and disordered regions.
Collapse
Affiliation(s)
- Emily M Grasso
- Department of Biology, Johns Hopkins University, Baltimore, Maryland; T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland
| | - Ananya Majumdar
- The Biomolecular NMR Center, Johns Hopkins University, Baltimore, Maryland
| | - James O Wrabl
- Department of Biology, Johns Hopkins University, Baltimore, Maryland
| | - Dominique P Frueh
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Vincent J Hilser
- Department of Biology, Johns Hopkins University, Baltimore, Maryland; T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland.
| |
Collapse
|
8
|
Rondon R, Wilson CJ. Engineering Alternate Ligand Recognition in the PurR Topology: A System of Novel Caffeine Biosensing Transcriptional Antirepressors. ACS Synth Biol 2021; 10:552-565. [PMID: 33689294 DOI: 10.1021/acssynbio.0c00582] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recent advances in synthetic biology and protein engineering have increased the number of allosteric transcription factors used to regulate independent promoters. These developments represent an important increase in our biological computing capacity, which will enable us to construct more sophisticated genetic programs for a broad range of biological technologies. However, the majority of these transcription factors are represented by the repressor phenotype (BUFFER), and require layered inversion to confer the antithetical logical function (NOT), requiring additional biological resources. Moreover, these engineered transcription factors typically utilize native ligand binding functions paired with alternate DNA binding functions. In this study, we have advanced the state-of-the-art by engineering and redesigning the PurR topology (a native antirepressor) to be responsive to caffeine, while mitigating responsiveness to the native ligand hypoxanthine-i.e., a deamination product of the input molecule adenine. Importantly, the resulting caffeine responsive transcription factors are not antagonized by the native ligand hypoxanthine. In addition, we conferred alternate DNA binding to the caffeine antirepressors, and to the PurR scaffold, creating 38 new transcription factors that are congruent with our current transcriptional programming structure. Finally, we leveraged this system of transcription factors to create integrated NOR logic and related feedback operations. This study represents the first example of a system of transcription factors (antirepressors) in which both the ligand binding site and the DNA binding functions were successfully engineered in tandem.
Collapse
Affiliation(s)
- Ronald Rondon
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
| | - Corey J. Wilson
- Georgia Institute of Technology, School of Chemical & Biomolecular Engineering, 311 Ferst Drive, Atlanta, Georgia 30332-0100, United States
| |
Collapse
|