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Boushehri S, Holey H, Brosz M, Gumbsch P, Pastewka L, Aponte-Santamaría C, Gräter F. O-glycans Expand Lubricin and Attenuate Its Viscosity and Shear Thinning. Biomacromolecules 2024. [PMID: 38815979 DOI: 10.1021/acs.biomac.3c01348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Lubricin, an intrinsically disordered glycoprotein, plays a pivotal role in facilitating smooth movement and ensuring the enduring functionality of synovial joints. The central domain of this protein serves as a source of this excellent lubrication and is characterized by its highly glycosylated, negatively charged, and disordered structure. However, the influence of O-glycans on the viscosity of lubricin remains unclear. In this study, we employ molecular dynamics simulations in the absence and presence of shear, along with continuum simulations, to elucidate the intricate interplay between O-glycans and lubricin and the impact of O-glycans on lubricin's conformational properties and viscosity. We found the presence of O-glycans to induce a more extended conformation in fragments of the disordered region of lubricin. These O-glycans contribute to a reduction in solution viscosity but at the same time weaken shear thinning at high shear rates, compared to nonglycosylated systems with the same density. This effect is attributed to the steric and electrostatic repulsion between the fragments, which prevents their conglomeration and structuring. Our computational study yields a mechanistic mechanism underlying previous experimental observations of lubricin and paves the way to a more rational understanding of its function in the synovial fluid.
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Affiliation(s)
- Saber Boushehri
- Heidelberg Institute for Theoretical Studies, Schloß-Wolfsbrunnenweg 35, Heidelberg 69118, Germany
- University of Heidelberg, Im Neuenheimer Feld 205, Heidelberg 69120, Germany
- Karlsruhe Institute of Technology (KIT), Karlsruhe 76131, Germany
| | - Hannes Holey
- Karlsruhe Institute of Technology (KIT), Karlsruhe 76131, Germany
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, Freiburg 79110, Germany
| | - Matthias Brosz
- Heidelberg Institute for Theoretical Studies, Schloß-Wolfsbrunnenweg 35, Heidelberg 69118, Germany
- University of Heidelberg, Im Neuenheimer Feld 205, Heidelberg 69120, Germany
| | - Peter Gumbsch
- Karlsruhe Institute of Technology (KIT), Karlsruhe 76131, Germany
- Fraunhofer IWM, Wöhlerstraße 11, Freiburg 79108, Germany
| | - Lars Pastewka
- Department of Microsystems Engineering, University of Freiburg, Georges-Köhler-Allee 103, Freiburg 79110, Germany
| | - Camilo Aponte-Santamaría
- Heidelberg Institute for Theoretical Studies, Schloß-Wolfsbrunnenweg 35, Heidelberg 69118, Germany
| | - Frauke Gräter
- Heidelberg Institute for Theoretical Studies, Schloß-Wolfsbrunnenweg 35, Heidelberg 69118, Germany
- University of Heidelberg, Im Neuenheimer Feld 205, Heidelberg 69120, Germany
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Downs M, Curran J, Zaia J, Sethi MK. Analysis of complex proteoglycans using serial proteolysis and EThcD provides deep N- and O-glycoproteomic coverage. Anal Bioanal Chem 2023; 415:6995-7009. [PMID: 37728749 PMCID: PMC10865727 DOI: 10.1007/s00216-023-04934-x] [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: 05/19/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/21/2023]
Abstract
Proteoglycans are a small but diverse family of proteins that play a wide variety of roles at the cell surface and in the extracellular matrix. In addition to their glycosaminoglycan (GAG) chains, they are N- and O-glycosylated. All of these types of glycosylation are crucial to their function but present a considerable analytical challenge. We describe the combination of serial proteolysis followed by the application of higher-energy collisional dissociation (HCD) and electron transfer/higher-energy collisional dissociation (EThcD) to optimize protein sequence coverage and glycopeptide identification from proteoglycans. In many cases, the use of HCD alone allows the identification of more glycopeptides. However, the localization of glycoforms on multiply glycosylated peptides has remained elusive. We demonstrate the use of EThcD for the confident assignment of glycan compositions on multiply glycosylated peptides. Dense glycosylation on proteoglycans is key to their biological function; thus, developing tools to identify and quantify doubly glycosylated peptides is of interest. Additionally, glycoproteomics searches identify glycopeptides in otherwise poorly covered regions of proteoglycans. The development of these and other analytical tools may permit glycoproteomic similarity comparisons in biological samples.
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Affiliation(s)
- Margaret Downs
- Department of Biochemistry and Cell Biology, Center for Biomedical Mass Spectrometry, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
| | - Jillian Curran
- Department of Biochemistry and Cell Biology, Center for Biomedical Mass Spectrometry, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
| | - Joseph Zaia
- Department of Biochemistry and Cell Biology, Center for Biomedical Mass Spectrometry, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA
- Bioinformatics Program, Boston University, Boston, MA, USA
| | - Manveen K Sethi
- Department of Biochemistry and Cell Biology, Center for Biomedical Mass Spectrometry, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA.
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Wang Y, Mou X, Ji Y, Pan F, Li S. Interaction of Macromolecular Chain with Phospholipid Membranes in Solutions: A Dissipative Particle Dynamics Simulation Study. Molecules 2023; 28:5790. [PMID: 37570760 PMCID: PMC10420874 DOI: 10.3390/molecules28155790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/24/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
The interaction between macromolecular chains and phospholipid membranes in aqueous solution was investigated using dissipative particle dynamics simulations. Two cases were considered, one in which the macromolecular chains were pulled along parallel to the membrane surfaces and another in which they were pulled vertical to the membrane surfaces. Several parameters, including the radius of gyration, shape factor, particle number, and order parameter, were used to investigate the interaction mechanisms during the dynamics processes by adjusting the pulling force strength of the chains. In both cases, the results showed that the macromolecular chains undergo conformational transitions from a coiled to a rod-like structure. Furthermore, the simulations revealed that the membranes can be damaged and repaired during the dynamic processes. The role of the pulling forces and the adsorption interactions between the chains and membranes differed in the parallel and perpendicular pulling cases. These findings contribute to our understanding of the interaction mechanisms between macromolecules and membranes, and they may have potential applications in biology and medicine.
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Affiliation(s)
- Yuane Wang
- Department of Physics, Wenzhou University, Wenzhou 325035, China; (Y.W.); (X.M.); (Y.J.)
| | - Xuankang Mou
- Department of Physics, Wenzhou University, Wenzhou 325035, China; (Y.W.); (X.M.); (Y.J.)
| | - Yongyun Ji
- Department of Physics, Wenzhou University, Wenzhou 325035, China; (Y.W.); (X.M.); (Y.J.)
| | - Fan Pan
- School of Data Science and Artificial Intelligence, Wenzhou University of Technology, Wenzhou 325035, China
| | - Shiben Li
- Department of Physics, Wenzhou University, Wenzhou 325035, China; (Y.W.); (X.M.); (Y.J.)
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Mann AS, Smith AM, Saltzherr JO, Gopinath A, Andresen Eguiluz RC. Glycosaminoglycans and glycoproteins influence the elastic response of synovial fluid nanofilms on model oxide surfaces. Colloids Surf B Biointerfaces 2022; 213:112407. [PMID: 35180655 DOI: 10.1016/j.colsurfb.2022.112407] [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: 11/15/2021] [Revised: 01/27/2022] [Accepted: 02/07/2022] [Indexed: 10/19/2022]
Abstract
Synovial fluid (SF) is the natural lubricant found in articulated joints, providing unique cartilage surface protecting films under confinement and relative motion. While it is known that the synergistic interactions of the macromolecular constituents provide its unique load-bearing and tribological performance, it is not fully understood how two of the main constituents, glycosaminoglycans (GAGs) and glycoproteins, regulate the formation and mechanics of robust load-bearing films. Here, we present evidence that the load-bearing capabilities, rather than the tribological performance, of the formed SF films depend strongly on its components' integrity. For this purpose, we used a combination of enzymatic treatments, quartz crystal microbalance with dissipation (QCM-D), and the surface forces apparatus (SFA) to characterize the formation and load-bearing capabilities of SF films on model oxide (i.e., silicates) surfaces. We find that, upon cleavage of proteins, the elasticity of the films is reduced and that cleaving GAGs results in irreversible (plastic) molecular re-arrangements of the film constituents when subjected to confinement. Understanding thin film mechanics of SF can provide insight into the progression of diseases, such as arthritis, but may also be applicable to the development of new implant surface treatments or new biomimetic lubricants.
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Affiliation(s)
- Amar S Mann
- Department of Materials Science and Engineering, University of California, Merced, CA 95344, USA
| | - Ariell M Smith
- Department of Materials Science and Engineering, University of California, Merced, CA 95344, USA
| | - Joyce O Saltzherr
- Department of Materials Science and Engineering, University of California, Merced, CA 95344, USA
| | - Arvind Gopinath
- Department of Bioengineering, University of California, Merced, CA 95344, USA; Health Sciences Research Institute, University of California, Merced, CA 95344, USA
| | - Roberto C Andresen Eguiluz
- Department of Materials Science and Engineering, University of California, Merced, CA 95344, USA; Health Sciences Research Institute, University of California, Merced, CA 95344, USA.
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