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Gibb CD, Tran TH, Gibb BC. Assessing Weak Anion Binding to Small Peptides. J Phys Chem B 2024; 128:3605-3613. [PMID: 38592238 PMCID: PMC11033870 DOI: 10.1021/acs.jpcb.4c00657] [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: 01/30/2024] [Revised: 03/11/2024] [Accepted: 03/22/2024] [Indexed: 04/10/2024]
Abstract
Since Hofmeister's seminal studies in the late 19th century, it has been known that salts and buffers can drastically affect the properties of peptides and proteins. These Hofmeister effects can be conceived of in terms of three distinct phenomena/mechanisms: water-salt interactions that indirectly induce the salting-out of a protein by water sequestration by the salt, and direct salt-protein interactions that can either salt-in or salt-out the protein. Unfortunately, direct salt-protein interactions responsible for Hofmeister effects are weak and difficult to quantify. As such, they are frequently construed of as being nonspecific. Nevertheless, there has been considerable effort to better specify these interactions. Here, we use pentapeptides to demonstrate the utility of the H-dimension of nuclear magnetic resonance (NMR) spectroscopy to assess anion binding using N-H signal shifts. We qualify binding using these, demonstrating the upfield shifts induced by anion association and revealing how they are much larger than the corresponding downfield shifts induced by magnetic susceptibility and other ionic strength change effects. We also qualify binding in terms of how the pattern of signal shifts changes with point mutations. In general, we find that the observed upfield shifts are small compared with those induced by anion binding to amide-based hosts, and MD simulations suggest that this is so. Thus, charge-diffuse anions associate mostly with the nonpolar regions of the peptide rather than directly interacting with the amide N-H groups. These findings reveal the utility of 1H NMR spectroscopy for qualifying affinity to peptides─even when affinity constants are very low─and serve as a benchmark for using NMR spectroscopy to study anion binding to more complex systems.
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Affiliation(s)
- Corinne
L. D. Gibb
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
| | - Thien H. Tran
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
| | - Bruce C. Gibb
- Department of Chemistry, Tulane University School of Science and Engineering, New Orleans, Louisiana 70118, United States
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Liang K, Zhao C, Song C, Zhao L, Qiu P, Wang S, Zhu J, Gong Z, Liu Z, Tang R, Fang X, Zhao Y. In Situ Biomimetic Mineralization of Bone-Like Hydroxyapatite in Hydrogel for the Acceleration of Bone Regeneration. ACS APPLIED MATERIALS & INTERFACES 2023; 15:292-308. [PMID: 36583968 DOI: 10.1021/acsami.2c16217] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A critical-sized bone defect, which cannot be repaired through self-healing, is a major challenge in clinical therapeutics. The combination of biomimetic hydrogels and nano-hydroxyapatite (nano-HAP) is a promising way to solve this problem by constructing an osteogenic microenvironment. However, it is challenging to generate nano-HAP with a similar morphology and structure to that of natural bone, which limits the improvement of bone regeneration hydrogels. Inspired by our previous works on organic-inorganic cocross-linking, here, we built a strong organic-inorganic interaction by cross-linking periosteum-decellularized extracellular matrix and calcium phosphate oligomers, which ensured the in situ mineralization of bone-like nano-HAP in hydrogels. The resulting biomimetic osteogenic hydrogel (BOH) promotes bone mineralization, construction of immune microenvironment, and angiogenesis improvement in vitro. The BOH exhibited acceleration of osteogenesis in vivo, achieving large-sized bone defect regeneration and remodeling within 8 weeks, which is superior to many previously reported hydrogels. This study demonstrates the important role of bone-like nano-HAP in osteogenesis, which deepens the understanding of the design of biomaterials for hard tissue repair. The in situ mineralization of bone-like nano-HAP emphasizes the advantages of inorganic ionic oligomers in the construction of organic-inorganic interaction, which provides an alternative method for the preparation of advanced biomimetic materials.
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Affiliation(s)
- Kaiyu Liang
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Chenchen Zhao
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang 310003, China
| | - Chenxin Song
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Lan Zhao
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Pengcheng Qiu
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Shengyu Wang
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Jinjin Zhu
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Zhe Gong
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Zhaoming Liu
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Key Laboratory of Excited-State Materials of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Ruikang Tang
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Xiangqian Fang
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
| | - Yueqi Zhao
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310016, China
- Key Laboratory of Musculoskeletal System Degeneration and Regeneration, Translational Research of Zhejiang Province, Hangzhou, Zhejiang 310016, China
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Zhao J, Dong T, Yu P, Wang J. Conformation and Metal Cation Binding of Zwitterionic Alanine Tripeptide in Saline Solutions by Infrared Vibrational Spectroscopy and Molecular Dynamics Simulations. J Phys Chem B 2021; 126:161-173. [PMID: 34968072 DOI: 10.1021/acs.jpcb.1c10034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, linear infrared (IR) spectroscopy and molecular dynamics (MD) simulations were used to examine the interaction of different metal cations (Na+, Ca2+, Mg2+, and Zn2+) with backbone (amide C═O) and C-terminal carboxylate (COO-) groups in zwitterionic alanine tripeptide (Ala3) in aqueous solutions with varying saline concentrations. Circular dichroism spectra and MD results suggest that Ala3 is predominantly in polyproline-II (PPII) conformation, whose amide-I and asymmetric carboxylate stretching IR vibration signatures are also supported by quantum-chemistry calculations. The zwitterionic form of Ala3 separates the two amide-I modes in frequency, which are weakly coupled modes, as revealed by two-dimensional IR measurement, and can be used to probe backbone-cation interactions at different scenarios (near charged or neutral chemical groups respectively). Cation concentration-dependent IR frequency red shifts in the amide-I mode are seen for both amide-I modes, whereas blue shifts are also seen in the amide-I mode far from the NH3+ group. The observed spectral changes are discussed from the perspective of the salting-in and salting-out abilities of the cations. In addition, all the metal cations studied here (except Zn2+) can specifically coordinate to the COO- group in bidentate and pseudo-bridging forms simultaneously. For Zn2+, only the pseudo-bridging form exists. Our results shed light on the macroscopic protein salting-in and salting-out phenomena from the perspective of key chemical bonds in peptides.
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Affiliation(s)
- Juan Zhao
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Tiantian Dong
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Pengyun Yu
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Jianping Wang
- Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.,University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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