1
|
Liu Z, Zhang Z, Yang L, Zhang Y, Li D, Zhang Q, Niu C, Zhang B, Zhai Y, Wang Z. Effect and mechanism of C-terminal cysteine on the properties of HEV p222 protein. Virology 2024; 595:110091. [PMID: 38718446 DOI: 10.1016/j.virol.2024.110091] [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: 02/17/2024] [Revised: 04/07/2024] [Accepted: 04/18/2024] [Indexed: 05/18/2024]
Abstract
Preliminary investigations have demonstrated that the cysteines located at the C-terminus of HEV ORF2 protein exhibits disulfide bonding capability during virus-like particles (VLPs) assembly. However, the effect and mechanism underlying the pairing of disulfide bonds formed by C627, C630, and C638 remains unclear. The p222 protein encompasses C-terminus and serves as a representative of HEV ORF2 to investigate the specific impacts of C627, C630, and C638. The three cysteines were subjected to site-directed mutagenesis and expressed in prokaryotes; Both the mutated proteins and p222 underwent polymerization except for p222A; Surprisingly, only p222 was observed as abundant spherical particles under transmission electron microscope (TEM); Stability and immunogenicity of the p222 exhibited higher than other mutated proteins; LC/MS/MS analysis identified four disulfide bonds in the p222. The novel findings suggest that the three cysteines contribute to structural and functional properties of ORF2 protein, highlighting the indispensability of each cysteine.
Collapse
Affiliation(s)
- Zhenzhen Liu
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Zhenzhen Zhang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Lanping Yang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Yongwen Zhang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Dong Li
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Qingling Zhang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Chao Niu
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Baobao Zhang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Yangyang Zhai
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China
| | - Zhenhui Wang
- College of Medicine, Henan Polytechnic University, Jiaozuo, 454000, Henan, China.
| |
Collapse
|
2
|
Teiar R, Sane F, Erol I, Nekoua MP, Lecouturier D, Boukherroub R, Durdağı S, Hober D, Drider D. Enterocin DD14 can inhibit the infection of eukaryotic cells with enveloped viruses. Arch Microbiol 2024; 206:269. [PMID: 38767708 DOI: 10.1007/s00203-024-04002-7] [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: 03/25/2024] [Revised: 05/02/2024] [Accepted: 05/11/2024] [Indexed: 05/22/2024]
Abstract
Bacteriocins are ribosomally synthesized bacterial peptides endowed with antibacterial, antiprotozoal, anticancer and antiviral activities. In the present study, we evaluated the antiviral activities of two bacteriocins, enterocin DD14 (EntDD14) and lacticaseicin 30, against herpes simplex virus type 1 (HSV-1), human coronavirus 229E (HCoV-229E) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Vero, Huh7 and Vero E6 cells, respectively. In addition, the interactions of these bacteriocins with the envelope glycoprotein D of HSV-1 and the receptor binding domains of HCoV-229E and SARS-CoV-2 have been computationally evaluated using protein-protein docking and molecular dynamics simulations. HSV-1 replication in Vero cells was inhibited by EntDD14 and, to a lesser extent, by lacticaseicin 30 added to cells after virus inoculation. EntDD14 and lacticaseicin 30 had no apparent antiviral activity against HCoV-229E; however, EntDD14 was able to inhibit SARS-CoV-2 in Vero E6 cells. Further studies are needed to elucidate the antiviral mechanism of these bacteriocins.
Collapse
Affiliation(s)
- Radja Teiar
- UMR Transfrontalière BioEcoAgro INRAe 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, YNCREA, Univ. Artois, Univ. Littoral Côte d'Opale, ICV-Institut Charles Viollette, Lille, 59000, France
| | - Famara Sane
- Univ. Lille, CHU Lille, Laboratoire de Virologie ULR3610, Lille, F-59000, France
| | - Ismail Erol
- Computational Drug Design Center (HITMER), Bahçeşehir University, Istanbul, Türkiye
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahçeşehir University, Istanbul, Türkiye
| | | | - Didier Lecouturier
- UMR Transfrontalière BioEcoAgro INRAe 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, YNCREA, Univ. Artois, Univ. Littoral Côte d'Opale, ICV-Institut Charles Viollette, Lille, 59000, France
| | - Rabah Boukherroub
- Univ. Lille, CNRS, Univ. Polytechnique Hauts-de-France, UMR, 8520 - IEMN, Lille, 59000, France
| | - Serdar Durdağı
- Computational Drug Design Center (HITMER), Bahçeşehir University, Istanbul, Türkiye
- Computational Biology and Molecular Simulations Laboratory, Department of Biophysics, School of Medicine, Bahçeşehir University, Istanbul, Türkiye
- Molecular Therapy Lab, Department of Pharmaceutical Chemistry, School of Pharmacy, Bahçeşehir University, Istanbul, Türkiye
| | - Didier Hober
- Univ. Lille, CHU Lille, Laboratoire de Virologie ULR3610, Lille, F-59000, France.
| | - Djamel Drider
- UMR Transfrontalière BioEcoAgro INRAe 1158, Univ. Lille, INRAE, Univ. Liège, UPJV, YNCREA, Univ. Artois, Univ. Littoral Côte d'Opale, ICV-Institut Charles Viollette, Lille, 59000, France.
| |
Collapse
|
3
|
Zhou Q, Lv S, Wang W, Zhu S, Xu J, Zheng M, Liu Y, Zhou Y, Sui X, Xiao Y. Remodeling mechanism of gel network structure of soy protein isolate amyloid fibrils mediated by cellulose nanocrystals. Carbohydr Polym 2024; 332:121919. [PMID: 38431397 DOI: 10.1016/j.carbpol.2024.121919] [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: 11/03/2023] [Revised: 01/18/2024] [Accepted: 02/05/2024] [Indexed: 03/05/2024]
Abstract
The differences in the gelling properties of soy protein isolate (SPI) and soy protein isolate amyloid fibrils (SAFs) as well as the role of cellulose nanocrystals (CNC) in regulating their gel behaviors were investigated in this study. The binding of CNC to β-conglycinin (7S), glycinin (11S), and SAFs was predominantly driven by non-covalent interactions. CNC addition reduced the particle size, turbidity, subunit segments, and crystallinity of SPI and SAFs, promoted the conversion of α-helix to β-sheet, improved the thermal stability, exposed more tyrosine and tryptophan residues, and enhanced the intermolecular interactions. A more regular and ordered lamellar network structure was formed in the SAFs-CNC composite gel, which could be conducive to the improvement of gel quality. This study would provide theoretical reference for the understanding of the regulatory mechanism of protein amyloid fibrils gelation as well as the high-value utilization of SAFs-CNC complex as a functional protein-based material or food ingredient in food field.
Collapse
Affiliation(s)
- Qianxin Zhou
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Sixu Lv
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Wenqi Wang
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Shanlong Zhu
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Jianxia Xu
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Mingming Zheng
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Yingnan Liu
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China.
| | - Yibin Zhou
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China
| | - Xiaonan Sui
- College of Food Science, Northeast Agricultural University, Harbin, 150030, China.
| | - Yaqing Xiao
- Key Laboratory of Jianghuai Agricultural Product Fine Processing and Resource Utilization of Ministry of Agriculture and Rural Affairs, State Key Laboratory of Tea Plant Biology and Utilization, School of Tea and Food Science & Technology, Anhui Agricultural University, Hefei, 230036, China.
| |
Collapse
|
4
|
Nam Y, Nguyen DL, Hoang T, Kim B, Lee JH, Do H. Engineered ice-binding protein (FfIBP) shows increased stability and resistance to thermal and chemical denaturation compared to the wildtype. Sci Rep 2024; 14:3234. [PMID: 38331970 PMCID: PMC10853241 DOI: 10.1038/s41598-024-53864-w] [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: 11/13/2023] [Accepted: 02/06/2024] [Indexed: 02/10/2024] Open
Abstract
Many polar organisms produce antifreeze proteins (AFPs) and ice-binding proteins (IBPs) to protect themselves from ice formation. As IBPs protect cells and organisms, the potential of IBPs as natural or biological cryoprotective agents (CPAs) for the cryopreservation of animal cells, such as oocytes and sperm, has been explored to increase the recovery rate after freezing-thawing. However, only a few IBPs have shown success in cryopreservation, possibly because of the presence of protein denaturants, such as dimethyl sulfoxide, alcohols, or ethylene glycol, in freezing buffer conditions, rendering the IBPs inactive. Therefore, we investigated the thermal and chemical stability of FfIBP isolated from Antarctic bacteria to assess its suitability as a protein-based impermeable cryoprotectant. A molecular dynamics (MD) simulation identified and generated stability-enhanced mutants (FfIBP_CC1). The results indicated that FfIBP_CC1 displayed enhanced resistance to denaturation at elevated temperatures and chemical concentrations, compared to wildtype FfIBP, and was functional in known CPAs while retaining ice-binding properties. Given that FfIBP shares an overall structure similar to DUF3494 IBPs, which are recognized as the most widespread IBP family, these findings provide important structural information on thermal and chemical stability, which could potentially be applied to other DUF3494 IBPs for future protein engineering.
Collapse
Affiliation(s)
- Yewon Nam
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
| | - Dieu Linh Nguyen
- Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Trang Hoang
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Bogeun Kim
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea
| | - Jun Hyuck Lee
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea.
| | - Hackwon Do
- Research Unit of Cryogenic Novel Material, Korea Polar Research Institute, Incheon, 21990, Republic of Korea.
- Department of Polar Sciences, University of Science and Technology, Incheon, 21990, Republic of Korea.
| |
Collapse
|
5
|
Kumar M, Rathore RS. Disallowed spots in protein structures. Biochim Biophys Acta Gen Subj 2023; 1867:130493. [PMID: 37865175 DOI: 10.1016/j.bbagen.2023.130493] [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: 05/29/2023] [Revised: 09/26/2023] [Accepted: 10/17/2023] [Indexed: 10/23/2023]
Abstract
Ramachandran (ϕ, ψ) steric map was introduced in 1963 to describe available conformation space for protein structures. Subsequently, residues were observed in high-energy disallowed regions of the map. To unequivocally identify the locations of disallowed conformations of residues, we got 36 noise-free protein structures (resolution ≤1 Å, Rwork/Rfree ≤ 0.10). These stringent criteria were applied to rule out data or model errors or any crystallographic disorders. No disallowed conformation was found in the dataset. Further, we also examined disallowed conformations in a larger dataset (resolution ≤1.5 Å, devoid of any model errors, or disorders). The observed locations of disallowed residues are referred as disallowed spots. These spots include short loops of 3-5 residues, and locations where residues participate in disulfide bonding or intramolecular interactions or inter-molecular interactions with neighboring water, metals or ligands. Conformational sampling revealed that short loops in between secondary structures hardly have any opportunity to relieve from conformational strain. Residues involved in interactions, which provide energetic compensation for high-energy conformational states, were relieved from strain once the causative interaction was removed. The present study aims to identify disallowed spots in the native state of proteins, wherein residues are forced to be trapped in high-energy disallowed conformations. Moreover, it was also observed that pre-Pro, Ser, Asp, trans-Pro, Val, Asn & Gly have higher tendency to occur in disallowed conformation, which could be attributed to factors such as conformational restrictions, residue propensity of secondary structures and compensating sidechain and mainchain interactions, stabilizing turn-mimics.
Collapse
Affiliation(s)
- Mayank Kumar
- Department of Bioinformatics, School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Gaya, Bihar 824236, India
| | - R S Rathore
- Department of Bioinformatics, School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Gaya, Bihar 824236, India.
| |
Collapse
|
6
|
Bitran A, Park K, Serebryany E, Shakhnovich EI. Co-translational formation of disulfides guides folding of the SARS-CoV-2 receptor binding domain. Biophys J 2023; 122:3238-3253. [PMID: 37422697 PMCID: PMC10465708 DOI: 10.1016/j.bpj.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 05/27/2023] [Accepted: 07/03/2023] [Indexed: 07/10/2023] Open
Abstract
Many secreted proteins, including viral proteins, contain multiple disulfide bonds. How disulfide formation is coupled to protein folding in the cell remains poorly understood at the molecular level. Here, we combine experiment and simulation to address this question as it pertains to the SARS-CoV-2 receptor binding domain (RBD). We show that the RBD can only refold reversibly if its native disulfides are present before folding. But in their absence, the RBD spontaneously misfolds into a nonnative, molten-globule-like state that is structurally incompatible with complete disulfide formation and that is highly prone to aggregation. Thus, the RBD native structure represents a metastable state on the protein's energy landscape with reduced disulfides, indicating that nonequilibrium mechanisms are needed to ensure native disulfides form before folding. Our atomistic simulations suggest that this may be achieved via co-translational folding during RBD secretion into the endoplasmic reticulum. Namely, at intermediate translation lengths, native disulfide pairs are predicted to come together with high probability, and thus, under suitable kinetic conditions, this process may lock the protein into its native state and circumvent highly aggregation-prone nonnative intermediates. This detailed molecular picture of the RBD folding landscape may shed light on SARS-CoV-2 pathology and molecular constraints governing SARS-CoV-2 evolution.
Collapse
Affiliation(s)
- Amir Bitran
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts; PhD Program in Biophysics, Harvard University, Cambridge, Massachusetts.
| | - Kibum Park
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Eugene Serebryany
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Eugene I Shakhnovich
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts.
| |
Collapse
|
7
|
Molinos M, Fiordalisi MF, Caldeira J, Almeida CR, Barbosa MA, Gonçalves RM. Alterations of bovine nucleus pulposus cells with aging. Aging Cell 2023; 22:e13873. [PMID: 37254638 PMCID: PMC10410011 DOI: 10.1111/acel.13873] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/19/2023] [Accepted: 04/29/2023] [Indexed: 06/01/2023] Open
Abstract
Aging is one of the major etiological factors driving intervertebral disc (IVD) degeneration, the main cause of low back pain. The nucleus pulposus (NP) includes a heterogeneous cell population, which is still poorly characterized. Here, we aimed to uncover main alterations in NP cells with aging. For that, bovine coccygeal discs from young (12 months) and old (10-16 years old) animals were dissected and primary NP cells were isolated. Gene expression and proteomics of fresh NP cells were performed. NP cells were labelled with propidium iodide and analysed by flow cytometry for the expression of CD29, CD44, CD45, CD146, GD2, Tie2, CD34 and Stro-1. Morphological cell features were also dissected by imaging flow cytometry. Elder NP cells (up-regulated bIL-6 and bMMP1 gene expression) presented lower percentages of CD29+, CD44+, CD45+ and Tie2+ cells compared with young NP cells (upregulated bIL-8, bCOL2A1 and bACAN gene expression), while GD2, CD146, Stro-1 and CD34 expression were maintained with age. NP cellulome showed an upregulation of proteins related to endoplasmic reticulum (ER) and melanosome independently of age, whereas proteins upregulated in elder NP cells were also associated with glycosylation and disulfide bonds. Flow cytometry analysis of NP cells disclosed the existence of 4 subpopulations with distinct auto-fluorescence and size with different dynamics along aging. Regarding cell morphology, aging increases NP cell area, diameter and vesicles. These results contribute to a better understanding of NP cells aging and highlighting potential anti-aging targets that can help to mitigate age-related disc disease.
Collapse
Affiliation(s)
- Maria Molinos
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| | - Morena F. Fiordalisi
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| | - Joana Caldeira
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
| | - Catarina R. Almeida
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
- iBiMED – Institute of Biomedicine, Department of Medical SciencesUniversity of AveiroAveiroPortugal
| | - Mário A. Barbosa
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| | - Raquel M. Gonçalves
- i3S – Instituto de Investigação e Inovação em SaúdeUniversidade do PortoPortoPortugal
- INEB – Instituto de Engenharia BiomédicaUniversidade do PortoPortoPortugal
- ICBAS – Instituto de Ciências Biomédicas Abel SalazarUniversidade do PortoPortoPortugal
| |
Collapse
|
8
|
Shen X, Zheng H, Han M, Xu X, Li B, Guo Q. Intermolecular forces regulate in-vitro digestion of whey protein emulsion gels: Towards controlled lipid release. J Colloid Interface Sci 2023; 649:245-254. [PMID: 37348344 DOI: 10.1016/j.jcis.2023.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/12/2023] [Accepted: 06/05/2023] [Indexed: 06/24/2023]
Abstract
HYPOTHESIS The utilization of emulsion-filled protein hydrogels for controlled lipid release in the gastrointestinal tract (GIT) displays great potential in drug delivery and obesity treatment. However, how intermolecular interactions among protein molecules influence lipid digestion of the gels is still understudied. EXPERIMENTS Differently structured whey protein emulsion gels were fabricated by heating emulsions with blocking of disulfide bonds (the "noncovalent" gel), noncovalent interactions (the "disulfide" gel), or neither of these (the "control" gel). The intermolecular interactions-gel structure-lipid digestion relationship was investigated by characterizing structural/mechanical properties of the gels and monitoring their dynamic breakdown in a simulated GIT. FINDINGS Although the disulfide-crosslinked protein network formed thick interfacial layers around oil droplets and resisted intestinal proteolysis, the "disulfide" gel had the fastest lipolysis rate, indicating that it could not inhibit the access of lipases to oil droplets. In contrast, the "noncovalent" gel was more susceptible to in-vitro digestion than the "control" gel because of lower gel strength, resulting in a faster lipolysis rate. This demonstrated that intermolecular disulfide bonds and noncovalent interactions played distinctive roles in the digestion of the gels; they represented the structural backbone and the infill in the gel structure, respectively.
Collapse
Affiliation(s)
- Xingxing Shen
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China; Maanshan Safety Inspection Center for Food and Drug, Maanshan Administration for Market Regulation, Maanshan 243000, China
| | - Hao Zheng
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China
| | - Menghan Han
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China
| | - Xiyu Xu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China
| | - Bingyi Li
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China
| | - Qing Guo
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruits and Vegetables Processing, China Agricultural University, Beijing 100083, China; Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture and Rural Affairs, Beijing, China; Beijing Key Laboratory of Food Non-Thermal Processing, Beijing 100083, China.
| |
Collapse
|
9
|
Tyler TJ, Durek T, Craik DJ. Native and Engineered Cyclic Disulfide-Rich Peptides as Drug Leads. Molecules 2023; 28:molecules28073189. [PMID: 37049950 PMCID: PMC10096437 DOI: 10.3390/molecules28073189] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
Bioactive peptides are a highly abundant and diverse group of molecules that exhibit a wide range of structural and functional variation. Despite their immense therapeutic potential, bioactive peptides have been traditionally perceived as poor drug candidates, largely due to intrinsic shortcomings that reflect their endogenous heritage, i.e., short biological half-lives and poor cell permeability. In this review, we examine the utility of molecular engineering to insert bioactive sequences into constrained scaffolds with desired pharmaceutical properties. Applying lessons learnt from nature, we focus on molecular grafting of cyclic disulfide-rich scaffolds (naturally derived or engineered), shown to be intrinsically stable and amenable to sequence modifications, and their utility as privileged frameworks in drug design.
Collapse
Affiliation(s)
- Tristan J. Tyler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Thomas Durek
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David J. Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia
| |
Collapse
|
10
|
Bitran A, Park K, Serebryany E, Shakhnovich EI. Cotranslational formation of disulfides guides folding of the SARS COV-2 receptor binding domain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.11.10.516025. [PMID: 36380756 PMCID: PMC9665344 DOI: 10.1101/2022.11.10.516025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Many secreted proteins contain multiple disulfide bonds. How disulfide formation is coupled to protein folding in the cell remains poorly understood at the molecular level. Here, we combine experiment and simulation to address this question as it pertains to the SARS-CoV-2 receptor binding domain (RBD). We show that, whereas RBD can refold reversibly when its disulfides are intact, their disruption causes misfolding into a nonnative molten-globule state that is highly prone to aggregation and disulfide scrambling. Thus, non-equilibrium mechanisms are needed to ensure disulfides form prior to folding in vivo. Our simulations suggest that co-translational folding may accomplish this, as native disulfide pairs are predicted to form with high probability at intermediate lengths, ultimately committing the RBD to its metastable native state and circumventing nonnative intermediates. This detailed molecular picture of the RBD folding landscape may shed light on SARS-CoV-2 pathology and molecular constraints governing SARS-CoV-2 evolution.
Collapse
|
11
|
Dupuy A, Ju LA, Chiu J, Passam FH. Mechano-Redox Control of Integrins in Thromboinflammation. Antioxid Redox Signal 2022; 37:1072-1093. [PMID: 35044225 DOI: 10.1089/ars.2021.0265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Significance: How mechanical forces and biochemical cues are coupled remains a miracle for many biological processes. Integrins, well-known adhesion receptors, sense changes in mechanical forces and reduction-oxidation reactions (redox) in their environment to mediate their adhesive function. The coupling of mechanical and redox function is a new area of investigation. Disturbance of normal mechanical forces and the redox balance occurs in thromboinflammatory conditions; atherosclerotic plaques create changes to the mechanical forces in the circulation. Diabetes induces redox changes in the circulation by the production of reactive oxygen species and vascular inflammation. Recent Advances: Integrins sense changes in the blood flow shear stress at the level of focal adhesions and respond to flow and traction forces by increased signaling. Talin, the integrin-actin linker, is a traction force sensor and adaptor. Oxidation and reduction of integrin disulfide bonds regulate their adhesion. A conserved disulfide bond in integrin αlpha IIb beta 3 (αIIbβ3) is directly reduced by the thiol oxidoreductase endoplasmic reticulum protein 5 (ERp5) under shear stress. Critical Issues: The coordination of mechano-redox events between the extracellular and intracellular compartments is an active area of investigation. Another fundamental issue is to determine the spatiotemporal arrangement of key regulators of integrins' mechanical and redox interactions. How thromboinflammatory conditions lead to mechanoredox uncoupling is relatively unexplored. Future Directions: Integrated approaches, involving disulfide bond biochemistry, microfluidic assays, and dynamic force spectroscopy, will aid in showing that cell adhesion constitutes a crossroad of mechano- and redox biology, within the same molecule, the integrin. Antioxid. Redox Signal. 37, 1072-1093.
Collapse
Affiliation(s)
- Alexander Dupuy
- Central Clinical School, Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, Australia.,Heart Research Institute, Newtown, Australia
| | - Lining Arnold Ju
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia.,Heart Research Institute, Newtown, Australia.,School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Darlington, Australia
| | - Joyce Chiu
- Charles Perkins Centre, The University of Sydney, Camperdown, Australia.,ACRF Centenary Cancer Research Centre, The Centenary Institute, Camperdown, Australia
| | - Freda H Passam
- Central Clinical School, Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia.,Charles Perkins Centre, The University of Sydney, Camperdown, Australia.,Heart Research Institute, Newtown, Australia
| |
Collapse
|
12
|
Shah A, Ghalsasi PS, Ghalsasi P. Effect of quasi hydrostatic and non hydrostatic pressure on long S–S bonded sodium dithionite (Na2S2O4): A Raman Spectroscopic study. J SOLID STATE CHEM 2022. [DOI: 10.1016/j.jssc.2022.123315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
13
|
Zhang JY, Yang BB, Yang YD, Wang R, Li L. Specific chiroptical sensing of cysteine via ultrasound-assisted formation of disulfide bonds in aqueous solution. ULTRASONICS SONOCHEMISTRY 2022; 86:106007. [PMID: 35436673 PMCID: PMC9036132 DOI: 10.1016/j.ultsonch.2022.106007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/04/2022] [Accepted: 04/10/2022] [Indexed: 06/14/2023]
Abstract
Cysteine (Cys) can serve as a biomarker to indicate diseases or disorders, and its chiral sensing has attracted increasing attention. Herein, we established an ultrasound-facilitated chiral sensing method for Cys using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) and electronic circular dichroism (ECD) spectroscopy. The formation of chiral disulfide bonds induced degenerate exciton coupling between two NBD chromophores, resulting in intense Cotton effects (CEs) of the sensing product. The anisotropy factor (g) was linearly correlated with the enantiomeric excess of Cys across the visible region (400-500 nm), and other natural amino acids or biothiols did not interfere with the detection. This ultrasound-promoted efficient and specific chiral sensing method of Cys has potential for application in the diagnosis of related diseases.
Collapse
Affiliation(s)
- Jun-Yao Zhang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Bei-Bei Yang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ya-Dong Yang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Ru Wang
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Li Li
- Beijing Key Laboratory of Active Substances Discovery and Druggability Evaluation, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
| |
Collapse
|
14
|
Catalano C, AL Mughram MH, Guo Y, Kellogg GE. 3D interaction homology: Hydropathic interaction environments of serine and cysteine are strikingly different and their roles adapt in membrane proteins. Curr Res Struct Biol 2021; 3:239-256. [PMID: 34693344 PMCID: PMC8517007 DOI: 10.1016/j.crstbi.2021.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/23/2021] [Accepted: 09/23/2021] [Indexed: 12/12/2022] Open
Abstract
Atomic-resolution protein structural models are prerequisites for many downstream activities like structure-function studies or structure-based drug discovery. Unfortunately, this data is often unavailable for some of the most interesting and therapeutically important proteins. Thus, computational tools for building native-like structural models from less-than-ideal experimental data are needed. To this end, interaction homology exploits the character, strength and loci of the sets of interactions that define a structure. Each residue type has its own limited set of backbone angle-dependent interaction motifs, as defined by their environments. In this work, we characterize the interactions of serine, cysteine and S-bridged cysteine in terms of 3D hydropathic environment maps. As a result, we explore several intriguing questions. Are the environments different between the isosteric serine and cysteine residues? Do some environments promote the formation of cystine S-S bonds? With the increasing availability of structural data for water-insoluble membrane proteins, are there environmental differences for these residues between soluble and membrane proteins? The environments surrounding serine and cysteine residues are dramatically different: serine residues are about 50% solvent exposed, while cysteines are only 10% exposed; the latter are more involved in hydrophobic interactions although there are backbone angle-dependent differences. Our analysis suggests that one driving force for -S-S- bond formation is a rather substantial increase in burial and hydrophobic interactions in cystines. Serine and cysteine become less and more, respectively, solvent-exposed in membrane proteins. 3D hydropathic environment maps are an evolving structure analysis tool showing promise as elements in a new protein structure prediction paradigm.
Collapse
Affiliation(s)
- Claudio Catalano
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Mohammed H. AL Mughram
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Youzhong Guo
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
| | - Glen E. Kellogg
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA, USA
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, USA
| |
Collapse
|
15
|
Tang P, Tan Z, Ehamparanathan V, Ren T, Hoffman L, Du C, Song Y, Tao L, Lewandowski A, Ghose S, Li ZJ, Liu S. Optimization and kinetic modeling of interchain disulfide bond reoxidation of monoclonal antibodies in bioprocesses. MAbs 2021; 12:1829336. [PMID: 33031716 PMCID: PMC7577745 DOI: 10.1080/19420862.2020.1829336] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Disulfide bonds play a crucial role in folding and structural stabilization of monoclonal antibodies (mAbs). Disulfide bond reduction may happen during the mAb manufacturing process, resulting in low molecular weight species and possible failure to meet product specifications. Although many mitigation strategies have been developed to prevent disulfide reduction, to the best of our knowledge, reforming disulfide bonds from the reduced antibody in manufacturing has not previously been reported. Here, we explored a novel rescue strategy in the downstream process to repair the broken disulfide bonds via in-vitro redox reactions on Protein A resin. Redox conditions including redox pair (cysteine/cystine ratio), pH, temperature, and reaction time were examined to achieve high antibody purity and a high reaction rate. Under the optimal redox condition, >90% reduced antibody could be reoxidized to form an intact antibody on Protein A resin in an hour. In addition, this study showed high flexibility on the range of the intact mAb fraction in the initial reduced mAb sample (the lower limit of intact mAb faction could be 14% based on the data reported in this study). Furthermore, a kinetic model based on elementary oxidative reactions was constructed to help optimize the reoxidation conditions and to predict product purity. Together, the deep understanding of interchain disulfide bond reoxidation, combined with the predictive kinetic model, provided a good foundation to implement a rescue strategy to generate high-purity antibodies with substantial cost savings in manufacturing processes.
Collapse
Affiliation(s)
- Peifeng Tang
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA.,Department of Paper and Bioprocess Engineering, The State University of New York College of Environmental Science and Forestry , Syracuse, NY, USA
| | - Zhijun Tan
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Vivekh Ehamparanathan
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Tingwei Ren
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Laurel Hoffman
- Global Product Development and Supply, Bristol-Myers Squibb Company , Pennington, NJ, USA
| | - Cheng Du
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Yuanli Song
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Li Tao
- Global Product Development and Supply, Bristol-Myers Squibb Company , Pennington, NJ, USA
| | - Angela Lewandowski
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Sanchayita Ghose
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Zheng Jian Li
- Global Product Development and Supply, Bristol-Myers Squibb Company , Devens, MA, USA
| | - Shijie Liu
- Department of Paper and Bioprocess Engineering, The State University of New York College of Environmental Science and Forestry , Syracuse, NY, USA
| |
Collapse
|
16
|
Alegre-Cebollada J. Protein nanomechanics in biological context. Biophys Rev 2021; 13:435-454. [PMID: 34466164 PMCID: PMC8355295 DOI: 10.1007/s12551-021-00822-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022] Open
Abstract
How proteins respond to pulling forces, or protein nanomechanics, is a key contributor to the form and function of biological systems. Indeed, the conventional view that proteins are able to diffuse in solution does not apply to the many polypeptides that are anchored to rigid supramolecular structures. These tethered proteins typically have important mechanical roles that enable cells to generate, sense, and transduce mechanical forces. To fully comprehend the interplay between mechanical forces and biology, we must understand how protein nanomechanics emerge in living matter. This endeavor is definitely challenging and only recently has it started to appear tractable. Here, I introduce the main in vitro single-molecule biophysics methods that have been instrumental to investigate protein nanomechanics over the last 2 decades. Then, I present the contemporary view on how mechanical force shapes the free energy of tethered proteins, as well as the effect of biological factors such as post-translational modifications and mutations. To illustrate the contribution of protein nanomechanics to biological function, I review current knowledge on the mechanobiology of selected muscle and cell adhesion proteins including titin, talin, and bacterial pilins. Finally, I discuss emerging methods to modulate protein nanomechanics in living matter, for instance by inducing specific mechanical loss-of-function (mLOF). By interrogating biological systems in a causative manner, these new tools can contribute to further place protein nanomechanics in a biological context.
Collapse
|
17
|
Zhang X, Xia Z, Liu X, Li J. The novel matrix protein hic7 of hyriopsis cumingii participates in the formation of the shell and pearl. Comp Biochem Physiol B Biochem Mol Biol 2021; 256:110640. [PMID: 34182125 DOI: 10.1016/j.cbpb.2021.110640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 10/21/2022]
Abstract
Shell matrix proteins have important roles in the biomineralization of shells. In this study, we isolated and identified a novel shell matrix protein gene, hic7, from the mussel Hyriopsis cumingii. The cDNA of hic7 was 459 bp long, including a 240-bp open reading frame. It encoded a 79 amino acid-long protein, with amino acids 1-19 constituting the signal peptide. The resulting hic7 is rich in cysteine (16.5%). After removing the signal peptide, the molecular weight was 8.85 kDa and the theoretical isoelectric point was 6.34, indicating that hic7 is a weakly acidic shell matrix protein. Hic7 is mainly expressed in the mantle tissue of H. cumingii. In situ hybridization showed hic7 signals at the edge and dorsal region of the mantle outer fold, indicating that it is related to the formation of the prismatic and nacreous layer of the shell. RNA interference indicated that when hic7 was inhibited by 80%, the crystal morphology of the prism and nacre layers of the shell were irregular and disordered. In addition, the expression of hic7 during the early development of the pearl sac indicated that it has an important role in the transformation of calcium carbonate crystals from a disordered to an orderly deposition pattern. These results suggest that matrix protein hic7 take part in constructing the framework of crystal nucleation and regulating the calcium carbonate crystal morphology of the nacreous and prismatic layers of shells and pearls.
Collapse
Affiliation(s)
- Xin Zhang
- Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Zhonghui Xia
- Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China
| | - Xiaojun Liu
- Department of Biotechnology and Biomedicine, Yangtze Delta Region Institute of Tsinghua University, Zhejiang 314000, China.
| | - Jiale Li
- Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China.
| |
Collapse
|
18
|
Ren T, Tan Z, Ehamparanathan V, Lewandowski A, Ghose S, Li ZJ. Antibody disulfide bond reduction and recovery during biopharmaceutical process development-A review. Biotechnol Bioeng 2021; 118:2829-2844. [PMID: 33844277 DOI: 10.1002/bit.27790] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 12/29/2022]
Abstract
Antibody disulfide bond reduction has been a challenging issue in monoclonal antibody manufacturing. It could lead to a decrease of product purity and failure to meet the targeted product profile and/or specifications. More importantly, disulfide bond reduction could also impact drug safety and efficacy. Scientists across the industry have been examining the root causes and developing mitigation strategies to address the challenge. In recent years, with the development of high titer mammalian cell culture processes to meet the rapidly growing demand for antibody biopharmaceuticals, disulfide bond reduction has been observed more frequently. Thus, it is necessary to continue evolving the disulfide reduction mitigation strategies and developing novel approaches to maintain high product quality. Additionally, in recent years as more complex molecules (such as bispecific and trispecific antibodies) emerge, the molecular heterogeneity due to incomplete formation of the interchain disulfide bonds becomes a more imperative challenging issue. Given the disulfide reduction challenges that biotech industry is facing, in this review, we provide a comprehensive scientific summary of the root cause analysis of disulfide reduction during process development of antibody therapeutics, mitigation strategies and its potential remediated recovery based on published papers. First, this paper intends to highlight different aspects of the root cause for disulfide reduction. Secondly, to provide a broader understanding of the disulfide bond reduction in downstream process, this paper discusses disulfide bond reduction impact on product stability, associated analytical methods for disulfide bond reduction detection and characterization, process control strategies as well as their manufacturing implementation. In addition, brief perspectives on the development of future mitigation strategies are also reviewed, including platform alignment, mitigation strategy application for the emerging new modalities such as bispecific and trispecific antibodies as well as using machine learning to identify molecule susceptibility of disulfide bond reduction. The data in this review are originated from the published papers.
Collapse
Affiliation(s)
- Tingwei Ren
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| | - Zhijun Tan
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| | - Vivekh Ehamparanathan
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| | - Angela Lewandowski
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| | - Sanchayita Ghose
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| | - Zheng Jian Li
- Biologics Development, Global Product Development and Supply, Bristol-Myers Squibb, Devens, Massachusetts
| |
Collapse
|
19
|
Abstract
Titin oxidation alters titin stiffness, which greatly contributes to overall myocardial stiffness. This stiffness is frequently increased in heart disease, such as diastolic heart failure. We have quantified the degree of oxidative titin changes in several murine heart and skeletal muscle models exposed to oxidant stress and mechanical load. Importantly, strain enhances in vivo oxidation of titin in the elastic region, but not the inextensible segment. The functional consequences include oxidation type-dependent effects on cardiomyocyte stiffness, titin-domain folding, phosphorylation, and inter-titin interactions. Thus, oxidative modifications stabilize the titin spring in a dynamic and reversible manner and help propagate changes in titin-based myocardial stiffness. Our findings pave the way for interventions that target the pathological stiffness of titin in disease. The relationship between oxidative stress and cardiac stiffness is thought to involve modifications to the giant muscle protein titin, which in turn can determine the progression of heart disease. In vitro studies have shown that S-glutathionylation and disulfide bonding of titin fragments could alter the elastic properties of titin; however, whether and where titin becomes oxidized in vivo is less certain. Here we demonstrate, using multiple models of oxidative stress in conjunction with mechanical loading, that immunoglobulin domains preferentially from the distal titin spring region become oxidized in vivo through the mechanism of unfolded domain oxidation (UnDOx). Via oxidation type-specific modification of titin, UnDOx modulates human cardiomyocyte passive force bidirectionally. UnDOx also enhances titin phosphorylation and, importantly, promotes nonconstitutive folding and aggregation of unfolded domains. We propose a mechanism whereby UnDOx enables the controlled homotypic interactions within the distal titin spring to stabilize this segment and regulate myocardial passive stiffness.
Collapse
|
20
|
Yang B, Liu Z, Liu H, Nash MA. Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes. Front Mol Biosci 2020; 7:85. [PMID: 32509800 PMCID: PMC7248566 DOI: 10.3389/fmolb.2020.00085] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.
Collapse
Affiliation(s)
- Byeongseon Yang
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Zhaowei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Haipei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Michael A. Nash
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| |
Collapse
|
21
|
Dahal N, Nowitzke J, Eis A, Popa I. Binding-Induced Stabilization Measured on the Same Molecular Protein Substrate Using Single-Molecule Magnetic Tweezers and Heterocovalent Attachments. J Phys Chem B 2020; 124:3283-3290. [DOI: 10.1021/acs.jpcb.0c00167] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Narayan Dahal
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Joel Nowitzke
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Annie Eis
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| | - Ionel Popa
- Department of Physics, University of Wisconsin-Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, United States
| |
Collapse
|
22
|
Liu H, Schittny V, Nash MA. Removal of a Conserved Disulfide Bond Does Not Compromise Mechanical Stability of a VHH Antibody Complex. NANO LETTERS 2019; 19:5524-5529. [PMID: 31257893 PMCID: PMC6975629 DOI: 10.1021/acs.nanolett.9b02062] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/28/2019] [Indexed: 05/28/2023]
Abstract
Single-domain VHH antibodies are promising reagents for medical therapy. A conserved disulfide bond within the VHH framework region is known to be critical for thermal stability, however, no prior studies have investigated its influence on the stability of VHH antibody-antigen complexes under mechanical load. Here, we used single-molecule force spectroscopy to test the influence of a VHH domain's conserved disulfide bond on the mechanical strength of the interaction with its antigen mCherry. We found that although removal of the disulfide bond through cysteine-to-alanine mutagenesis significantly lowered VHH domain denaturation temperature, it had no significant impact on the mechanical strength of the VHH:mCherry interaction with complex rupture occurring at ∼60 pN at 103-104 pN/sec regardless of disulfide bond state. These results demonstrate that mechanostable binding interactions can be built on molecular scaffolds that may be thermodynamically compromised at equilibrium.
Collapse
Affiliation(s)
- Haipei Liu
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Valentin Schittny
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| | - Michael A. Nash
- Department
of Chemistry, University of Basel, 4058 Basel, Switzerland
- Department
of Biosystems Science and Engineering, ETH
Zurich, 4058 Basel, Switzerland
| |
Collapse
|
23
|
Gunnoo M, Cazade PA, Orlowski A, Chwastyk M, Liu H, Ta DT, Cieplak M, Nash M, Thompson D. Steered molecular dynamics simulations reveal the role of Ca 2+ in regulating mechanostability of cellulose-binding proteins. Phys Chem Chem Phys 2019; 20:22674-22680. [PMID: 30132772 DOI: 10.1039/c8cp00925b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The conversion of cellulosic biomass into biofuels requires degradation of the biomass into fermentable sugars. The most efficient natural cellulase system for carrying out this conversion is an extracellular multi-enzymatic complex named the cellulosome. In addition to temperature and pH stability, mechanical stability is important for functioning of cellulosome domains, and experimental techniques such as Single Molecule Force Spectroscopy (SMFS) have been used to measure the mechanical strength of several cellulosomal proteins. Molecular dynamics computer simulations provide complementary atomic-resolution quantitative maps of domain mechanical stability for identification of experimental leads for protein stabilization. In this study, we used multi-scale steered molecular dynamics computer simulations, benchmarked against new SMFS measurements, to measure the intermolecular contacts that confer high mechanical stability to a family 3 Carbohydrate Binding Module protein (CBM3) derived from the archetypal Clostridium thermocellum cellulosome. Our data predicts that electrostatic interactions in the calcium binding pocket modulate the mechanostability of the cellulose-binding module, which provides an additional design rule for the rational re-engineering of designer cellulosomes for biotechnology. Our data offers new molecular insights into the origins of mechanostability in cellulose binding domains and gives leads for synthesis of more robust cellulose-binding protein modules. On the other hand, simulations predict that insertion of a flexible strand can promote alternative unfolding pathways and dramatically reduce the mechanostability of the carbohydrate binding module, which gives routes to rational design of tailormade fingerprint complexes for force spectroscopy experiments.
Collapse
Affiliation(s)
- Melissabye Gunnoo
- Department of Physics, Bernal Institute, University of Limerick, V94 T9PX, Ireland.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Tiberti M, Lechner BD, Fornili A. Binding Pockets in Proteins Induced by Mechanical Stress. J Chem Theory Comput 2019; 15:1-6. [PMID: 30525608 DOI: 10.1021/acs.jctc.8b00755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We report the first observation of a pocket that opens as a result of a mechanical force applied to an Ig-like domain from the cardiac muscle. This previously unseen mechanism of pocket formation is revealed by molecular dynamics simulations under force. Preliminary investigations show that this "mechano-pocket" is potentially druggable and could be found in other domains from the same fold family, suggesting the existence of a general mechanism of pocket formation under mechanical stress.
Collapse
Affiliation(s)
- Matteo Tiberti
- School of Biological and Chemical Sciences , Queen Mary University of London , London E1 4NS , United Kingdom
| | - Bob-Dan Lechner
- School of Biological and Chemical Sciences , Queen Mary University of London , London E1 4NS , United Kingdom
| | - Arianna Fornili
- School of Biological and Chemical Sciences , Queen Mary University of London , London E1 4NS , United Kingdom.,The Thomas Young Centre for Theory and Simulation of Materials , London , United Kingdom
| |
Collapse
|
25
|
Herrero-Galán E, Martínez-Martín I, Alegre-Cebollada J. Redox regulation of protein nanomechanics in health and disease: Lessons from titin. Redox Biol 2018; 21:101074. [PMID: 30584979 PMCID: PMC6305763 DOI: 10.1016/j.redox.2018.101074] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/22/2018] [Accepted: 12/07/2018] [Indexed: 01/11/2023] Open
Abstract
The nanomechanics of sarcomeric proteins is a key contributor to the mechanical output of muscle. Among them, titin emerges as a main target for the regulation of the stiffness of striated muscle. In the last years, single-molecule experiments by Atomic Force Microscopy (AFM) have demonstrated that redox posttranslational modifications are strong modulators of the mechanical function of titin. Here, we provide an overview of the recent development of the redox mechanobiology of titin, and suggest avenues of research to better understand how the stiffness of molecules, cells and tissues are modulated by redox signaling in health and disease.
Collapse
|
26
|
Kilgore HR, Raines RT. n→π* Interactions Modulate the Properties of Cysteine Residues and Disulfide Bonds in Proteins. J Am Chem Soc 2018; 140:17606-17611. [PMID: 30403347 DOI: 10.1021/jacs.8b09701] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Noncovalent interactions are ubiquitous in biology, taking on roles that include stabilizing the conformation of and assembling biomolecules, and providing an optimal environment for enzymatic catalysis. Here, we describe a noncovalent interaction that engages the sulfur atoms of cysteine residues and disulfide bonds in proteins-their donation of electron density into an antibonding orbital of proximal amide carbonyl groups. This n→ π* interaction tunes the reactivity of the CXXC motif, which is the critical feature of thioredoxin and other enzymes involved in redox homeostasis. In particular, an n→ π* interaction lowers the p Ka value of the N-terminal cysteine residue of the motif, which is the nucleophile that initiates catalysis. In addition, the interplay between disulfide n→ π* interactions and C5 hydrogen bonds leads to hyperstable β-strands. Finally, n→ π* interactions stabilize vicinal disulfide bonds, which are naturally diverse in function. These previously unappreciated n→ π* interactions are strong and underlie the ability of cysteine residues and disulfide bonds to engage in the structure and function of proteins.
Collapse
Affiliation(s)
- Henry R Kilgore
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Ronald T Raines
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| |
Collapse
|
27
|
Hildebrand N, Wei G, Köppen S, Colombi Ciacchi L. Simulated and experimental force spectroscopy of lysozyme on silica. Phys Chem Chem Phys 2018; 20:19595-19605. [PMID: 30009290 DOI: 10.1039/c8cp03747g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The force spectra of proteins detaching from oxide surfaces measured by atomic force microscopy (AFM) often present complex patterns of peaks, which are difficult to correlate with individual bond-breaking events at the atomic scale. In this work we rationalize experimental AFM force spectra of hen-egg-white lysozyme detaching from silica by means of all-atom steered molecular dynamics (SMD) simulations. In particular, we demonstrate that the native tertiary structure of lysozyme is preserved if, and only if, its four intramolecular disulfide bridges are intact. Otherwise, the protein pulled off the surface undergoes severe unfolding, which is well captured by SMD simulations in explicit solvent. Implicit solvent simulations, on the contrary, wrongly predict protein unfolding even in the presence of S-S bridges, due to the lack of additional structural stabilization provided by the water's hydrogen-bond network within and surrounding the protein. On the basis of our combined experimental and theoretical findings, we infer that the rugged force spectra characteristic of lysozyme/silica interfaces are not due to the successive breaking of internal disulfide bonds leading to partial unfolding events. Rather, they reflect the detachment of several molecules bound to the same AFM tip, each anchored to the surface via multiple hydrogen and ionic bonds.
Collapse
Affiliation(s)
- Nils Hildebrand
- Hybrid Materials Interfaces Group, Faculty Production Engineering, Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany.
| | | | | | | |
Collapse
|
28
|
Mechanical architecture and folding of E. coli type 1 pilus domains. Nat Commun 2018; 9:2758. [PMID: 30013059 PMCID: PMC6048123 DOI: 10.1038/s41467-018-05107-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 05/03/2018] [Indexed: 12/16/2022] Open
Abstract
Uropathogenic Escherichia coli attach to tissues using pili type 1. Each pilus is composed by thousands of coiled FimA domains followed by the domains of the tip fibrillum, FimF-FimG-FimH. The domains are linked by non-covalent β-strands that must resist mechanical forces during attachment. Here, we use single-molecule force spectroscopy to measure the mechanical contribution of each domain to the stability of the pilus and monitor the oxidative folding mechanism of a single Fim domain assisted by periplasmic FimC and the oxidoreductase DsbA. We demonstrate that pilus domains bear high mechanical stability following a hierarchy by which domains close to the tip are weaker than those close to or at the pilus rod. During folding, this remarkable stability is achieved by the intervention of DsbA that not only forms strategic disulfide bonds but also serves as a chaperone assisting the folding of the domains. The pilus type 1 of uropathogenic E. coli must resist mechanical forces to remain attached to the epithelium. Here the authors use single-molecule force spectroscopy to demonstrate a hierarchy of mechanical stability among the pilus domains and show that the oxidoreductase DsbA also acts as a folding chaperone on the domains.
Collapse
|
29
|
Schönfelder J, Alonso-Caballero A, De Sancho D, Perez-Jimenez R. The life of proteins under mechanical force. Chem Soc Rev 2018; 47:3558-3573. [PMID: 29473060 DOI: 10.1039/c7cs00820a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Although much of our understanding of protein folding comes from studies of isolated protein domains in bulk, in the cellular environment the intervention of external molecular machines is essential during the protein life cycle. During the past decade single molecule force spectroscopy techniques have been extremely useful to deepen our understanding of these interventional molecular processes, as they allow for monitoring and manipulating mechanochemical events in individual protein molecules. Here, we review some of the critical steps in the protein life cycle, starting with the biosynthesis of the nascent polypeptide chain in the ribosome, continuing with the folding supported by chaperones and the translocation into different cell compartments, and ending with proteolysis in the proteasome. Along these steps, proteins experience molecular forces often combined with chemical transformations, affecting their folding and structure, which are measured or mimicked in the laboratory by the application of force with a single molecule apparatus. These mechanochemical reactions can potentially be used as targets for fighting against diseases. Inspired by these insightful experiments, we devise an outlook on the emerging field of mechanopharmacology, which reflects an alternative paradigm for drug design.
Collapse
|
30
|
Gu J, Tong H, Sun L, Lin Z. Molecular dynamics perspective on the thermal stability of mandelate racemase. J Biomol Struct Dyn 2018; 37:383-393. [PMID: 29334318 DOI: 10.1080/07391102.2018.1427631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mandelate racemase from Pseudomonas putida is a promising candidate for the dynamic kinetic resolution of α-hydroxy carboxylic acids. In the present study, the thermal stability of mandelate racemase was investigated through molecular dynamics simulations in the temperature range of 303-363 K, which can guide the design of mandelate racemase with higher stability. The basic features such as radius of gyration, surface accessibility, and secondary structure content suggested the instability of mandelate racemase at high temperatures. With increase in temperature, α-helix content reduced significantly, especially the α-helices exposed to the environment. At the simulation time scale considered, intra-protein hydrogen bonds, hydrogen bonds between protein and water decreased at 363 K, while the number of salt-bridges increased. The long-distance networks remarkably changed at 363 K. A considerable number of long-lived (percentage existence time higher than 90%) hydrogen bonds and Cα contacts were lost. Root mean square fluctuation analysis revealed regions with high fluctuation, which should be helpful in the reengineering of mandelate racemase for enhanced thermal stability.
Collapse
Affiliation(s)
- Jiali Gu
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Hongfei Tong
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Laiyu Sun
- a College of Life Sciences , Huzhou University , Huzhou , Zhejiang , 313000 , China
| | - Zhijian Lin
- b Novel Search Center , Zhejiang Institute of Scientific and Technological Information , Hangzhou , Zhejiang , 310052 , China
| |
Collapse
|
31
|
Disulfide isomerization reactions in titin immunoglobulin domains enable a mode of protein elasticity. Nat Commun 2018; 9:185. [PMID: 29330363 PMCID: PMC5766482 DOI: 10.1038/s41467-017-02528-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 12/04/2017] [Indexed: 12/31/2022] Open
Abstract
The response of titin to mechanical forces is a major determinant of the function of the heart. When placed under a pulling force, the unstructured regions of titin uncoil while its immunoglobulin (Ig) domains unfold and extend. Using single-molecule atomic force microscopy, we show that disulfide isomerization reactions within Ig domains enable a third mechanism of titin elasticity. Oxidation of Ig domains leads to non-canonical disulfide bonds that stiffen titin while enabling force-triggered isomerization reactions to more extended states of the domains. Using sequence and structural analyses, we show that 21% of titin’s I-band Ig domains contain a conserved cysteine triad that can engage in disulfide isomerization reactions. We propose that imbalance of the redox status of myocytes can have immediate consequences for the mechanical properties of the sarcomere via alterations of the oxidation state of titin domains. Titin regulates myocyte stiffness through uncoiling and unfolding but these two processes cannot fully explain its elasticity. Here, the authors use atomic force microscopy to study the properties of titin disulfide bonds, showing that disulfide isomerization represents a third mode of titin elasticity.
Collapse
|