1
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Chang YC, Cao Z, Chen WT, Huang WC. Effects of stand-alone polar residue on membrane protein stability and structure. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184325. [PMID: 38653423 DOI: 10.1016/j.bbamem.2024.184325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 04/25/2024]
Abstract
Helical membrane proteins generally have a hydrophobic nature, with apolar side chains comprising the majority of the transmembrane (TM) helices. However, whenever polar side chains are present in the TM domain, they often exert a crucial role in structural interactions with other polar residues, such as TM helix associations and oligomerization. Moreover, polar residues in the TM region also often participate in protein functions, such as the Schiff base bonding between Lys residues and retinal in rhodopsin-like membrane proteins. Although many studies have focused on these functional polar residues, our understanding of stand-alone polar residues that are energetically unfavored in TM helixes is limited. Here, we adopted bacteriorhodopsin (bR) as a model system and systematically mutated 17 of its apolar Leu or Phe residues to polar Asn. Stability measurements of the resulting mutants revealed that all of these polar substitutions reduced bR stability to various extents, and the extent of destabilization of each mutant bR is also correlated to different structural factors, such as the relative accessible surface area and membrane depth of the mutation site. Structural analyses of these Asn residues revealed that they form sidechain-to-backbone hydrogen bonds that alleviate the unfavorable energetics in hydrophobic and apolar surroundings. Our results indicate that membrane proteins are able to accommodate certain stand-alone polar residues in the TM region without disrupting overall structures.
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Affiliation(s)
- Yu-Chu Chang
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; International Ph.D. Program for Cell Therapy and Regeneration Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Zheng Cao
- Department of Chemistry and Biochemistry, Molecular Biology Institute, UCLA, Los Angeles, CA 90095, United States of America
| | - Wai-Ting Chen
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wei-Chun Huang
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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2
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Surya W, Honey SS, Torres J. Flavivirus Zika NS4A protein forms large oligomers in liposomes and in mild detergent. Sci Rep 2024; 14:12533. [PMID: 38822066 PMCID: PMC11143224 DOI: 10.1038/s41598-024-63407-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/28/2024] [Indexed: 06/02/2024] Open
Abstract
In flaviviruses such as Dengue or Zika, non-structural (NS) NS4A protein forms homo-oligomers, participates in membrane remodelling and is critical for virulence. In both viruses, mature NS4A has the same length and three predicted hydrophobic domains. The oligomers formed by Dengue NS4A are reported to be small (n = 2, 3), based on denaturing SDS gels, but no high-resolution structure of a flavivirus NS4A protein is available, and the size of the oligomer in lipid membranes is not known. Herein we show that crosslinking Zika NS4A protein in lipid membranes results in oligomers at least up to hexamers. Further, sedimentation velocity shows that NS4A in mild detergent C14-betaine appears to be in fast equilibrium between at least two species, where one is smaller, and the other larger, than a trimer or a tetramer. Consistently, sedimentation equilibrium data was best fitted to a model involving an equilibrium between dimers (n = 2) and hexamers (n = 6). Overall, the large, at least hexameric, oligomers obtained herein in liposomes and in mild detergent are more likely to represent the forms of NS4A present in cell membranes.
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Affiliation(s)
- Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Shwe Sin Honey
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore
| | - Jaume Torres
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551, Singapore.
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3
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Situ AJ, Ulmer TS. Comparison of Integrin αIIbβ3 Transmembrane Association in Vesicles and Bicelles. Biochemistry 2023. [PMID: 37279176 DOI: 10.1021/acs.biochem.3c00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Membrane proteins are commonly reconstituted in membrane mimics exhibiting discontinuous lipid bilayers. In contrast, the continuous membranes of cells are conceptually best represented by large unilamellar vesicles (LUVs). Here, we compared the thermodynamic stability of the integrin αIIbβ3 transmembrane (TM) complex between vesicles and bicelles to assess the consequence of this simplification. In LUVs, we further evaluated the strength of the αIIb(G972S)-β3(V700T) interaction that corresponds to the hydrogen bond interaction postulated for β2 integrins. An upper limit of 0.9 kcal/mol was estimated for superior TM complex stabilization in LUVs relative to bicelles. Compared to the αIIbβ3 TM complex stability in LUVs of 5.6 ± 0.2 kcal/mol, this limit is modest, indicating that bicelles performed well relative to LUVs. The implementation of β3(V700T) alleviated αIIb(G972S) destabilization by 0.4 ± 0.2 kcal/mol in confirmation of relatively weak hydrogen bonding. Interestingly, the hydrogen bond adjusts the TM complex stability to a level that is not achievable by merely varying the residue corresponding to αIIb(Gly972).
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Affiliation(s)
- Alan J Situ
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
| | - Tobias S Ulmer
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
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4
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Qing R, Hao S, Smorodina E, Jin D, Zalevsky A, Zhang S. Protein Design: From the Aspect of Water Solubility and Stability. Chem Rev 2022; 122:14085-14179. [PMID: 35921495 PMCID: PMC9523718 DOI: 10.1021/acs.chemrev.1c00757] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Indexed: 12/13/2022]
Abstract
Water solubility and structural stability are key merits for proteins defined by the primary sequence and 3D-conformation. Their manipulation represents important aspects of the protein design field that relies on the accurate placement of amino acids and molecular interactions, guided by underlying physiochemical principles. Emulated designer proteins with well-defined properties both fuel the knowledge-base for more precise computational design models and are used in various biomedical and nanotechnological applications. The continuous developments in protein science, increasing computing power, new algorithms, and characterization techniques provide sophisticated toolkits for solubility design beyond guess work. In this review, we summarize recent advances in the protein design field with respect to water solubility and structural stability. After introducing fundamental design rules, we discuss the transmembrane protein solubilization and de novo transmembrane protein design. Traditional strategies to enhance protein solubility and structural stability are introduced. The designs of stable protein complexes and high-order assemblies are covered. Computational methodologies behind these endeavors, including structure prediction programs, machine learning algorithms, and specialty software dedicated to the evaluation of protein solubility and aggregation, are discussed. The findings and opportunities for Cryo-EM are presented. This review provides an overview of significant progress and prospects in accurate protein design for solubility and stability.
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Affiliation(s)
- Rui Qing
- State
Key Laboratory of Microbial Metabolism, School of Life Sciences and
Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Media
Lab, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- The
David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Shilei Hao
- Media
Lab, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Key
Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400030, China
| | - Eva Smorodina
- Department
of Immunology, University of Oslo and Oslo
University Hospital, Oslo 0424, Norway
| | - David Jin
- Avalon GloboCare
Corp., Freehold, New Jersey 07728, United States
| | - Arthur Zalevsky
- Laboratory
of Bioinformatics Approaches in Combinatorial Chemistry and Biology, Shemyakin−Ovchinnikov Institute of Bioorganic
Chemistry RAS, Moscow 117997, Russia
| | - Shuguang Zhang
- Media
Lab, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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5
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Hong H, Choi HK, Yoon TY. Untangling the complexity of membrane protein folding. Curr Opin Struct Biol 2022; 72:237-247. [PMID: 34995926 DOI: 10.1016/j.sbi.2021.11.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 11/15/2022]
Abstract
Delineating the folding steps of helical-bundle membrane proteins has been a challenging task. Many questions remain unanswered, including the conformation and stability of the states populated during folding, the shape of the energy barriers between the states, and the role of lipids as a solvent in mediating the folding. Recently, theoretical frames have matured to a point that permits detailed dissection of the folding steps, and advances in experimental techniques at both single-molecule and ensemble levels enable selective modulation of specific steps for quantitative determination of the folding energy landscapes. We also discuss how lipid molecules would play an active role in shaping the folding energy landscape of membrane proteins, and how folding of multi-domain membrane proteins can be understood based on our current knowledge. We conclude this review by offering an outlook for emerging questions in the study of membrane protein folding.
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Affiliation(s)
- Heedeok Hong
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA.
| | - Hyun-Kyu Choi
- Wallace H. Coulter Department of Biomedical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul, 08826, South Korea.
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6
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Kratochvil HT, Newberry RW, Mensa B, Mravic M, DeGrado WF. Spiers Memorial Lecture: Analysis and de novo design of membrane-interactive peptides. Faraday Discuss 2021; 232:9-48. [PMID: 34693965 PMCID: PMC8979563 DOI: 10.1039/d1fd00061f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Membrane-peptide interactions play critical roles in many cellular and organismic functions, including protection from infection, remodeling of membranes, signaling, and ion transport. Peptides interact with membranes in a variety of ways: some associate with membrane surfaces in either intrinsically disordered conformations or well-defined secondary structures. Peptides with sufficient hydrophobicity can also insert vertically as transmembrane monomers, and many associate further into membrane-spanning helical bundles. Indeed, some peptides progress through each of these stages in the process of forming oligomeric bundles. In each case, the structure of the peptide and the membrane represent a delicate balance between peptide-membrane and peptide-peptide interactions. We will review this literature from the perspective of several biologically important systems, including antimicrobial peptides and their mimics, α-synuclein, receptor tyrosine kinases, and ion channels. We also discuss the use of de novo design to construct models to test our understanding of the underlying principles and to provide useful leads for pharmaceutical intervention of diseases.
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Affiliation(s)
- Huong T Kratochvil
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Robert W Newberry
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Bruk Mensa
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
| | - Marco Mravic
- Department of Integrative Structural and Computational Biology, Scripps Research Institute, La Jolla, CA 92037, USA
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California - San Francisco, San Francisco, CA 94158, USA.
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7
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Extremely Thermostabilizing Core Mutations in Coiled-Coil Mimetic Proteins of HIV-1 gp41 Produce Diverse Effects on Target Binding but Do Not Affect Their Inhibitory Activity. Biomolecules 2021; 11:biom11040566. [PMID: 33921495 PMCID: PMC8069472 DOI: 10.3390/biom11040566] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 11/16/2022] Open
Abstract
A promising strategy to neutralize HIV-1 is to target the gp41 spike subunit to block membrane fusion with the cell. We previously designed a series of single-chain proteins (named covNHR) that mimic the trimeric coiled-coil structure of the gp41 N-terminal heptad repeat (NHR) region and potently inhibit HIV-1 cell infection by avidly binding the complementary C-terminal heptad repeat (CHR) region. These proteins constitute excellent tools to understand the structural and thermodynamic features of this therapeutically important interaction. Gp41, as with many coiled-coil proteins, contains in core positions of the NHR trimer several highly conserved, buried polar residues, the role of which in gp41 structure and function is unclear. Here we produced three covNHR mutants by substituting each triad of polar residues for the canonical isoleucine. The mutants preserve their helical structure and show an extremely increased thermal stability. However, increased hydrophobicity enhances their self-association. Calorimetric analyses show a marked influence of mutations on the binding thermodynamics of CHR-derived peptides. The mutations do not affect however the in vitro HIV-1 inhibitory activity of the proteins. The results support a role of buried core polar residues in maintaining structural uniqueness and promoting an energetic coupling between conformational stability and NHR-CHR binding.
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8
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Small-residue packing motifs modulate the structure and function of a minimal de novo membrane protein. Sci Rep 2020; 10:15203. [PMID: 32938984 PMCID: PMC7495484 DOI: 10.1038/s41598-020-71585-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/26/2020] [Indexed: 11/08/2022] Open
Abstract
Alpha-helical integral membrane proteins contain conserved sequence motifs that are known to be important in helix packing. These motifs are a promising starting point for the construction of artificial proteins, but their potential has not yet been fully explored. Here, we study the impact of introducing a common natural helix packing motif to the transmembrane domain of a genetically-encoded and structurally dynamic de novo membrane protein. The resulting construct is an artificial four-helix bundle with lipophilic regions that are defined only by the amino acids L, G, S, A and W. This minimal proto-protein could be recombinantly expressed by diverse prokaryotic and eukaryotic hosts and was found to co-sediment with cellular membranes. The protein could be extracted and purified in surfactant micelles and was monodisperse and stable in vitro, with sufficient structural definition to support the rapid binding of a heme cofactor. The reduction in conformational diversity imposed by this design also enhances the nascent peroxidase activity of the protein-heme complex. Unexpectedly, strains of Escherichia coli expressing this artificial protein specifically accumulated zinc protoporphyrin IX, a rare cofactor that is not used by natural metalloenzymes. Our results demonstrate that simple sequence motifs can rigidify elementary membrane proteins, and that orthogonal artificial membrane proteins can influence the cofactor repertoire of a living cell. These findings have implications for rational protein design and synthetic biology.
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9
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Abstract
Proteins are molecular machines whose function depends on their ability to achieve complex folds with precisely defined structural and dynamic properties. The rational design of proteins from first-principles, or de novo, was once considered to be impossible, but today proteins with a variety of folds and functions have been realized. We review the evolution of the field from its earliest days, placing particular emphasis on how this endeavor has illuminated our understanding of the principles underlying the folding and function of natural proteins, and is informing the design of macromolecules with unprecedented structures and properties. An initial set of milestones in de novo protein design focused on the construction of sequences that folded in water and membranes to adopt folded conformations. The first proteins were designed from first-principles using very simple physical models. As computers became more powerful, the use of the rotamer approximation allowed one to discover amino acid sequences that stabilize the desired fold. As the crystallographic database of protein structures expanded in subsequent years, it became possible to construct proteins by assembling short backbone fragments that frequently recur in Nature. The second set of milestones in de novo design involves the discovery of complex functions. Proteins have been designed to bind a variety of metals, porphyrins, and other cofactors. The design of proteins that catalyze hydrolysis and oxygen-dependent reactions has progressed significantly. However, de novo design of catalysts for energetically demanding reactions, or even proteins that bind with high affinity and specificity to highly functionalized complex polar molecules remains an importnant challenge that is now being achieved. Finally, the protein design contributed significantly to our understanding of membrane protein folding and transport of ions across membranes. The area of membrane protein design, or more generally of biomimetic polymers that function in mixed or non-aqueous environments, is now becoming increasingly possible.
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10
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Mravic M, Thomaston JL, Tucker M, Solomon PE, Liu L, DeGrado WF. Packing of apolar side chains enables accurate design of highly stable membrane proteins. Science 2019; 363:1418-1423. [PMID: 30923216 DOI: 10.1126/science.aav7541] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 02/28/2019] [Indexed: 12/21/2022]
Abstract
The features that stabilize the structures of membrane proteins remain poorly understood. Polar interactions contribute modestly, and the hydrophobic effect contributes little to the energetics of apolar side-chain packing in membranes. Disruption of steric packing can destabilize the native folds of membrane proteins, but is packing alone sufficient to drive folding in lipids? If so, then membrane proteins stabilized by this feature should be readily designed and structurally characterized-yet this has not been achieved. Through simulation of the natural protein phospholamban and redesign of variants, we define a steric packing code underlying its assembly. Synthetic membrane proteins designed using this code and stabilized entirely by apolar side chains conform to the intended fold. Although highly stable, the steric complementarity required for their folding is surprisingly stringent. Structural informatics shows that the designed packing motif recurs across the proteome, emphasizing a prominent role for precise apolar packing in membrane protein folding, stabilization, and evolution.
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Affiliation(s)
- Marco Mravic
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jessica L Thomaston
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Maxwell Tucker
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Paige E Solomon
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Lijun Liu
- State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China. .,DLX Scientific, Lawrence, KS 66049, USA
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA.
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11
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Programmable design of orthogonal protein heterodimers. Nature 2018; 565:106-111. [PMID: 30568301 DOI: 10.1038/s41586-018-0802-y] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 11/08/2018] [Indexed: 11/09/2022]
Abstract
Specificity of interactions between two DNA strands, or between protein and DNA, is often achieved by varying bases or side chains coming off the DNA or protein backbone-for example, the bases participating in Watson-Crick pairing in the double helix, or the side chains contacting DNA in TALEN-DNA complexes. By contrast, specificity of protein-protein interactions usually involves backbone shape complementarity1, which is less modular and hence harder to generalize. Coiled-coil heterodimers are an exception, but the restricted geometry of interactions across the heterodimer interface (primarily at the heptad a and d positions2) limits the number of orthogonal pairs that can be created simply by varying side-chain interactions3,4. Here we show that protein-protein interaction specificity can be achieved using extensive and modular side-chain hydrogen-bond networks. We used the Crick generating equations5 to produce millions of four-helix backbones with varying degrees of supercoiling around a central axis, identified those accommodating extensive hydrogen-bond networks, and used Rosetta to connect pairs of helices with short loops and to optimize the remainder of the sequence. Of 97 such designs expressed in Escherichia coli, 65 formed constitutive heterodimers, and the crystal structures of four designs were in close agreement with the computational models and confirmed the designed hydrogen-bond networks. In cells, six heterodimers were fully orthogonal, and in vitro-following mixing of 32 chains from 16 heterodimer designs, denaturation in 5 M guanidine hydrochloride and reannealing-almost all of the interactions observed by native mass spectrometry were between the designed cognate pairs. The ability to design orthogonal protein heterodimers should enable sophisticated protein-based control logic for synthetic biology, and illustrates that nature has not fully explored the possibilities for programmable biomolecular interaction modalities.
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12
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Lu P, Min D, DiMaio F, Wei KY, Vahey MD, Boyken SE, Chen Z, Fallas JA, Ueda G, Sheffler W, Mulligan VK, Xu W, Bowie JU, Baker D. Accurate computational design of multipass transmembrane proteins. Science 2018; 359:1042-1046. [PMID: 29496880 DOI: 10.1126/science.aaq1739] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/11/2018] [Indexed: 01/01/2023]
Abstract
The computational design of transmembrane proteins with more than one membrane-spanning region remains a major challenge. We report the design of transmembrane monomers, homodimers, trimers, and tetramers with 76 to 215 residue subunits containing two to four membrane-spanning regions and up to 860 total residues that adopt the target oligomerization state in detergent solution. The designed proteins localize to the plasma membrane in bacteria and in mammalian cells, and magnetic tweezer unfolding experiments in the membrane indicate that they are very stable. Crystal structures of the designed dimer and tetramer-a rocket-shaped structure with a wide cytoplasmic base that funnels into eight transmembrane helices-are very close to the design models. Our results pave the way for the design of multispan membrane proteins with new functions.
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Affiliation(s)
- Peilong Lu
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Duyoung Min
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California, Los Angeles (UCLA), CA 90095, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Kathy Y Wei
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Michael D Vahey
- Department of Bioengineering and Biophysics Group, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Scott E Boyken
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Zibo Chen
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Jorge A Fallas
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - George Ueda
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - William Sheffler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Vikram Khipple Mulligan
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Wenqing Xu
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California, Los Angeles (UCLA), CA 90095, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. .,Institute for Protein Design, University of Washington, Seattle, WA 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
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13
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Maguire JB, Boyken SE, Baker D, Kuhlman B. Rapid Sampling of Hydrogen Bond Networks for Computational Protein Design. J Chem Theory Comput 2018; 14:2751-2760. [PMID: 29652499 DOI: 10.1021/acs.jctc.8b00033] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hydrogen bond networks play a critical role in determining the stability and specificity of biomolecular complexes, and the ability to design such networks is important for engineering novel structures, interactions, and enzymes. One key feature of hydrogen bond networks that makes them difficult to rationally engineer is that they are highly cooperative and are not energetically favorable until the hydrogen bonding potential has been satisfied for all buried polar groups in the network. Existing computational methods for protein design are ill-equipped for creating these highly cooperative networks because they rely on energy functions and sampling strategies that are focused on pairwise interactions. To enable the design of complex hydrogen bond networks, we have developed a new sampling protocol in the molecular modeling program Rosetta that explicitly searches for sets of amino acid mutations that can form self-contained hydrogen bond networks. For a given set of designable residues, the protocol often identifies many alternative sets of mutations/networks, and we show that it can readily be applied to large sets of residues at protein-protein interfaces or in the interior of proteins. The protocol builds on a recently developed method in Rosetta for designing hydrogen bond networks that has been experimentally validated for small symmetric systems but was not extensible to many larger protein structures and complexes. The sampling protocol we describe here not only recapitulates previously validated designs with performance improvements but also yields viable hydrogen bond networks for cases where the previous method fails, such as the design of large, asymmetric interfaces relevant to engineering protein-based therapeutics.
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Affiliation(s)
- Jack B Maguire
- Program in Bioinformatics and Computational Biology , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
| | - Scott E Boyken
- Department of Biochemistry , University of Washington , Seattle , Washington 98195 , United States.,Institute for Protein Design , University of Washington , Seattle , Washington 98195 , United States
| | - David Baker
- Department of Biochemistry , University of Washington , Seattle , Washington 98195 , United States.,Institute for Protein Design , University of Washington , Seattle , Washington 98195 , United States.,Howard Hughes Medical Institute , University of Washington , Seattle , Washington 98195 , United States
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States.,Lineberger Comprehensive Cancer Center , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599 , United States
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14
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Cao Z, Hutchison JM, Sanders CR, Bowie JU. Backbone Hydrogen Bond Strengths Can Vary Widely in Transmembrane Helices. J Am Chem Soc 2017; 139:10742-10749. [PMID: 28692798 PMCID: PMC5560243 DOI: 10.1021/jacs.7b04819] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
![]()
Although
backbone hydrogen bonds in transmembrane (TM) helices
have the potential to be very strong due to the low dielectric and
low water environment of the membrane, their strength has never been
assessed experimentally. Moreover, variations in hydrogen bond strength
might be necessary to facilitate the TM helix breaking and bending
that is often needed to satisfy functional imperatives. Here we employed
equilibrium hydrogen/deuterium fractionation factors to measure backbone
hydrogen bond strengths in the TM helix of the amyloid precursor protein
(APP). We find an enormous range of hydrogen bond free energies, with
some weaker than water–water hydrogen bonds and some over 6
kcal/mol stronger than water–water hydrogen bonds. We find
that weak hydrogen bonds are at or near preferred γ-secretase
cleavage sites, suggesting that the sequence of APP and possibly other
cleaved TM helices may be designed, in part, to make their backbones
accessible for cleavage. The finding that hydrogen bond strengths
in a TM helix can vary widely has implications for membrane protein
function, dynamics, evolution, and design.
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Affiliation(s)
- Zheng Cao
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
| | - James M Hutchison
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California , Los Angeles, California 90095, United States
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15
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Pike DH, Nanda V. Empirical estimation of local dielectric constants: Toward atomistic design of collagen mimetic peptides. Biopolymers 2016; 104:360-70. [PMID: 25784456 DOI: 10.1002/bip.22644] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/06/2015] [Accepted: 03/08/2015] [Indexed: 12/21/2022]
Abstract
One of the key challenges in modeling protein energetics is the treatment of solvent interactions. This is particularly important in the case of peptides, where much of the molecule is highly exposed to solvent due to its small size. In this study, we develop an empirical method for estimating the local dielectric constant based on an additive model of atomic polarizabilities. Calculated values match reported apparent dielectric constants for a series of Staphylococcus aureus nuclease mutants. Calculated constants are used to determine screening effects on Coulombic interactions and to determine solvation contributions based on a modified Generalized Born model. These terms are incorporated into the protein modeling platform protCAD, and benchmarked on a data set of collagen mimetic peptides for which experimentally determined stabilities are available. Computing local dielectric constants using atomistic protein models and the assumption of additive atomic polarizabilities is a rapid and potentially useful method for improving electrostatics and solvation calculations that can be applied in the computational design of peptides.
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Affiliation(s)
- Douglas H Pike
- Department of Biochemistry and Molecular Biology, Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854
| | - Vikas Nanda
- Department of Biochemistry and Molecular Biology, Center for Advanced Biotechnology and Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, 08854
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16
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In Vivo Analysis of Infectivity, Fusogenicity, and Incorporation of a Mutagenic Viral Glycoprotein Library Reveals Determinants for Virus Incorporation. J Virol 2016; 90:6502-14. [PMID: 27147747 DOI: 10.1128/jvi.00804-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Enveloped viruses utilize transmembrane surface glycoproteins to gain entry into target cells. Glycoproteins from diverse viral families can be incorporated into nonnative viral particles in a process termed pseudotyping; however, the molecular mechanisms governing acquisition of these glycoproteins are poorly understood. For murine leukemia virus envelope (MLV Env) glycoprotein, incorporation into foreign viral particles has been shown to be an active process, but it does not appear to be caused by direct interactions among viral proteins. In this study, we coupled in vivo selection systems with Illumina next-generation sequencing (NGS) to test hundreds of thousands of MLV Env mutants for the ability to be enriched in viral particles and to perform other glycoprotein functions. NGS analyses on a subset of these mutants predicted that the residues important for incorporation are in the membrane-proximal external region (MPER), particularly W127 and W137, and the residues in the membrane-spanning domain (MSD) and also immediately flanking it (T140 to L163). These predictions were validated by directly measuring the impact of mutations in these regions on fusogenicity, infectivity, and incorporation. We suggest that these two regions dictate pseudotyping through interactions with specific lipid environments formed during viral assembly. IMPORTANCE Researchers from numerous fields routinely exploit the ability to manipulate viral tropism by swapping viral surface proteins. However, this process, termed pseudotyping, is poorly understood at the molecular level. For murine leukemia virus envelope (MLV Env) glycoprotein, incorporation into foreign viral particles is an active process, but it does not appear to occur through direct viral protein-protein interactions. In this study, we tested hundreds of thousands of MLV Env mutants for the ability to be enriched in viral particles as well as perform other glycoprotein functions. Our analyses on a subset of these mutants predict that the glycoprotein regions embedded in and immediately flanking the viral membrane dictate active incorporation into viral particles. We suggest that pseudotyping occurs through specific lipid-protein interactions at the viral assembly site.
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17
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Boyken SE, Chen Z, Groves B, Langan RA, Oberdorfer G, Ford A, Gilmore JM, Xu C, DiMaio F, Pereira JH, Sankaran B, Seelig G, Zwart PH, Baker D. De novo design of protein homo-oligomers with modular hydrogen-bond network-mediated specificity. Science 2016; 352:680-7. [PMID: 27151862 PMCID: PMC5497568 DOI: 10.1126/science.aad8865] [Citation(s) in RCA: 222] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/23/2016] [Indexed: 12/26/2022]
Abstract
In nature, structural specificity in DNA and proteins is encoded differently: In DNA, specificity arises from modular hydrogen bonds in the core of the double helix, whereas in proteins, specificity arises largely from buried hydrophobic packing complemented by irregular peripheral polar interactions. Here, we describe a general approach for designing a wide range of protein homo-oligomers with specificity determined by modular arrays of central hydrogen-bond networks. We use the approach to design dimers, trimers, and tetramers consisting of two concentric rings of helices, including previously not seen triangular, square, and supercoiled topologies. X-ray crystallography confirms that the structures overall, and the hydrogen-bond networks in particular, are nearly identical to the design models, and the networks confer interaction specificity in vivo. The ability to design extensive hydrogen-bond networks with atomic accuracy enables the programming of protein interaction specificity for a broad range of synthetic biology applications; more generally, our results demonstrate that, even with the tremendous diversity observed in nature, there are fundamentally new modes of interaction to be discovered in proteins.
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Affiliation(s)
- Scott E Boyken
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Zibo Chen
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Graduate Program in Biological Physics, Structure, and Design, University of Washington, Seattle, WA 98195, USA
| | - Benjamin Groves
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Robert A Langan
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Gustav Oberdorfer
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Department of Computer Science and Engineering, University of Washington, Seattle, WA 98195, USA
| | - Alex Ford
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Jason M Gilmore
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Chunfu Xu
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Frank DiMaio
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA
| | - Jose Henrique Pereira
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50/3, 8010-Graz, Austria. Joint BioEnergy Institute, Emeryville, CA 94608, USA
| | - Banumathi Sankaran
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Georg Seelig
- Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA. Berkeley Center for Structural Biology, Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Peter H Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. The Center for Advanced Mathematics for Energy Research Applications, Lawrence Berkeley National Laboratories, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA. Institute for Protein Design, University of Washington, Seattle, WA 98195, USA. Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA.
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18
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Lizatović R, Aurelius O, Stenström O, Drakenberg T, Akke M, Logan D, André I. A De Novo Designed Coiled-Coil Peptide with a Reversible pH-Induced Oligomerization Switch. Structure 2016; 24:946-55. [DOI: 10.1016/j.str.2016.03.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/18/2016] [Accepted: 03/24/2016] [Indexed: 12/01/2022]
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19
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The membrane- and soluble-protein helix-helix interactome: similar geometry via different interactions. Structure 2015; 23:527-541. [PMID: 25703378 DOI: 10.1016/j.str.2015.01.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/17/2014] [Accepted: 01/06/2015] [Indexed: 12/25/2022]
Abstract
α Helices are a basic unit of protein secondary structure and therefore the interaction between helices is crucial to understanding tertiary and higher-order folds. Comparing subtle variations in the structural and sequence motifs between membrane and soluble proteins sheds light on the different constraints faced by each environment and elucidates the complex puzzle of membrane protein folding. Here, we demonstrate that membrane and water-soluble helix pairs share a small number of similar folds with various interhelical distances. The composition of the residues that pack at the interface between corresponding motifs shows that hydrophobic residues tend to be more enriched in the water-soluble class of structures and small residues in the transmembrane class. The latter group facilitates packing via sidechain- and backbone-mediated hydrogen bonds within the low-dielectric membrane milieu. The helix-helix interactome space, with its associated sequence preferences and accompanying hydrogen-bonding patterns, should be useful for engineering, prediction, and design of protein structure.
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20
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Jacso T, Bardiaux B, Broecker J, Fiedler S, Baerwinkel T, Mainz A, Fink U, Vargas C, Oschkinat H, Keller S, Reif B. The Mechanism of Denaturation and the Unfolded State of the α-Helical Membrane-Associated Protein Mistic. J Am Chem Soc 2013; 135:18884-91. [DOI: 10.1021/ja408644f] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Tomas Jacso
- Center
for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany
- Helmholtz-Zentrum
München, Deutsches Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Benjamin Bardiaux
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Jana Broecker
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Straße
13, 67663 Kaiserslautern, Germany
| | - Sebastian Fiedler
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Straße
13, 67663 Kaiserslautern, Germany
| | - Tom Baerwinkel
- Center
for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany
- Helmholtz-Zentrum
München, Deutsches Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Andi Mainz
- Center
for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Uwe Fink
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Carolyn Vargas
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Straße
13, 67663 Kaiserslautern, Germany
| | - Hartmut Oschkinat
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
| | - Sandro Keller
- Molecular
Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Straße
13, 67663 Kaiserslautern, Germany
| | - Bernd Reif
- Center
for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching, Germany
- Helmholtz-Zentrum
München, Deutsches Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
- Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Straße 10, 13125 Berlin-Buch, Germany
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21
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Nanda V, Hsieh D, Davis A. Prediction and design of outer membrane protein-protein interactions. Methods Mol Biol 2013; 1063:183-96. [PMID: 23975778 DOI: 10.1007/978-1-62703-583-5_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein-protein interactions (PPI) play central roles in biological processes, motivating us to understand the structural basis underlying affinity and specificity. In this chapter, we focus on biochemical and computational design strategies of assessing and detecting PPIs of β-barrel outer membrane proteins (OMPs). A few case studies are presented highlighting biochemical techniques used to dissect the energetics of oligomerization and determine amino acids forming the key interactions of the PPI sites. Current computational strategies for detecting/predicting PPIs are introduced, and examples of computational and rational engineering strategies applied to OMPs are presented.
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Affiliation(s)
- Vikas Nanda
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School-UMDNJ, Piscataway, NJ, USA
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22
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Bowie JU. Membrane protein folding: how important are hydrogen bonds? Curr Opin Struct Biol 2010; 21:42-9. [PMID: 21075614 DOI: 10.1016/j.sbi.2010.10.003] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2010] [Accepted: 10/19/2010] [Indexed: 11/28/2022]
Abstract
Water is an inhospitable environment for protein hydrogen bonds because it is polarizable and capable of forming competitive hydrogen bonds. In contrast, the apolar core of a biological membrane seems like an ideal environment for hydrogen bonds, and it has long been assumed that hydrogen bonding should be a powerful force driving membrane protein folding. Nevertheless, while backbone hydrogen bonds may be much stronger in membrane proteins, experimental measurements indicate that side chain hydrogen bond strengths are not strikingly different in membrane and water soluble proteins. How is this possible? I argue that model compounds in apolar solvents do not adequately describe the system because the protein itself is ignored. The protein chain provides a rich source of competitive hydrogen bonds and a polarizable environment that can weaken hydrogen bonds. Thus, just like water soluble proteins, evolution can drive the creation of potent hydrogen bonds in membrane proteins where necessary, but mitigating forces in their environment must still be overcome.
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Affiliation(s)
- James U Bowie
- Department of Chemistry and Biochemistry, UCLA-DOE Institute of Genomics and Proteomics, Molecular Biology Institute, University of California, Los Angeles, USA.
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23
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Method to measure strong protein-protein interactions in lipid bilayers using a steric trap. Proc Natl Acad Sci U S A 2010; 107:19802-7. [PMID: 21041662 DOI: 10.1073/pnas.1010348107] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Measuring high affinity protein-protein interactions in membranes is extremely challenging because there are limitations to how far the interacting components can be diluted in bilayers. Here we show that a steric trap can be employed for stable membrane interactions. We couple dissociation to a competitive binding event so that dissociation can be driven by increasing the affinity or concentration of the competitor. The steric trap design used here links monovalent streptavidin binding to dissociation of biotinylated partners. Application of the steric trap method to the well-characterized glycophorin A transmembrane helix (GpATM) reveals a dimer that is dramatically stabilized by 4-5 kcal/mol in palmitoyloleoylphosphatidylcholine bilayers compared to detergent. We also find larger effects of mutations at the dimer interface in bilayers compared to detergent suggesting that the dimer is more organized in a membrane environment. The high affinity we measure for GpATM in bilayers indicates that a membrane vesicle many orders of magnitude larger than a bacterial cell would be required to measure the dissociation constant using traditional dilution methods. Thus, steric trapping can open new biological systems to experimental scrutiny in natural bilayer environments.
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24
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Bordag N, Keller S. α-Helical transmembrane peptides: A “Divide and Conquer” approach to membrane proteins. Chem Phys Lipids 2010; 163:1-26. [PMID: 19682979 DOI: 10.1016/j.chemphyslip.2009.07.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 11/26/2022]
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25
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Yao QX, Pan L, Jin XH, Li J, Ju ZF, Zhang J. Bipyridinium Array-Type Porous Polymer Displaying Hydrogen Storage, Charge-Transfer-Type Guest Inclusion, and Tunable Magnetic Properties. Chemistry 2009; 15:11890-7. [DOI: 10.1002/chem.200901707] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Charge-transfer host complex with channel-like cavity using disubstituted-1,1′-bi-2-naphthol and benzylviologen. Tetrahedron Lett 2009. [DOI: 10.1016/j.tetlet.2009.07.090] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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Kandasamy SK, Lee DK, Nanga RP, Xu J, Santos JS, Larson RG, Ramamoorthy A. Solid-state NMR and molecular dynamics simulations reveal the oligomeric ion-channels of TM2-GABAA stabilized by intermolecular hydrogen bonding. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:686-95. [DOI: 10.1016/j.bbamem.2008.11.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/31/2008] [Accepted: 11/03/2008] [Indexed: 11/16/2022]
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28
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Moore DT, Berger BW, DeGrado WF. Protein-protein interactions in the membrane: sequence, structural, and biological motifs. Structure 2008; 16:991-1001. [PMID: 18611372 PMCID: PMC3771515 DOI: 10.1016/j.str.2008.05.007] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/25/2008] [Accepted: 05/30/2008] [Indexed: 01/10/2023]
Abstract
Single-span transmembrane (TM) helices have structural and functional roles well beyond serving as mere anchors to tether water-soluble domains in the vicinity of the membrane. They frequently direct the assembly of protein complexes and mediate signal transduction in ways analogous to small modular domains in water-soluble proteins. This review highlights different sequence and structural motifs that direct TM assembly and discusses their roles in diverse biological processes. We believe that TM interactions are potential therapeutic targets, as evidenced by natural proteins that modulate other TM interactions and recent developments in the design of TM-targeting peptides.
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Affiliation(s)
- David T. Moore
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
| | - Bryan W. Berger
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
| | - William F. DeGrado
- Department of Biochemistry and Molecular Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6059, USA
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29
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MacCallum JL, Bennett WFD, Tieleman DP. Partitioning of amino acid side chains into lipid bilayers: results from computer simulations and comparison to experiment. ACTA ACUST UNITED AC 2007; 129:371-7. [PMID: 17438118 PMCID: PMC2154372 DOI: 10.1085/jgp.200709745] [Citation(s) in RCA: 226] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Justin L MacCallum
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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30
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Johnson RM, Rath A, Deber CM. The position of the Gly-xxx-Gly motif in transmembrane segments modulates dimer affinityThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Membrane Proteins in Health and Disease. Biochem Cell Biol 2006; 84:1006-12. [PMID: 17215886 DOI: 10.1139/o06-192] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although the intrinsic low solubility of membrane proteins presents challenges to their high-resolution structure determination, insight into the amino acid sequence features and forces that stabilize their folds has been provided through study of sequence-dependent helix–helix interactions between single transmembrane (TM) helices. While the stability of helix–helix partnerships mediated by the Gly-xxx-Gly (GG4) motif is known to be generally modulated by distal interfacial residues, it has not been established whether the position of this motif, with respect to the ends of a given TM segment, affects dimer affinity. Here we examine the relationship between motif position and affinity in the homodimers of 2 single-spanning membrane protein TM sequences: glycophorin A (GpA) and bacteriophage M13 coat protein (MCP). Using the TOXCAT assay for dimer affinity on a series of GpA and MCP TM segments that have been modified with either 4 Leu residues at each end or with 8 Leu residues at the N-terminal end, we show that in each protein, centrally located GG4 motifs are capable of stronger helix–helix interactions than those proximal to TM helix ends, even when surrounding interfacial residues are maintained. The relative importance of GG4 motifs in stabilizing helix–helix interactions therefore must be considered not only in its specific residue context but also in terms of the location of the interactive surface relative to the N and C termini of α-helical TM segments.
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Affiliation(s)
- Rachel M Johnson
- Division of Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
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