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13C NMR Spectroscopic Studies of Intra- and Intermolecular Interactions of Amino Acid Derivatives and Peptide Derivatives in Solutions. ORGANICS 2022. [DOI: 10.3390/org3010003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
13C NMR spectroscopic investigations were conducted for various amino acid derivatives and peptides. It was observed that 13C NMR chemical shifts of the carbonyl carbons are correlated with the solvent polarities, but the extent depends on the structures. The size of the functional groups and inter- and intra-molecular hydrogen bonding appear to be the major contributors for this tendency.
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Tanaka T, Abe Y, Cheng CJ, Tanaka R, Naito A, Asakura T. Development of Small-Diameter Elastin-Silk Fibroin Vascular Grafts. Front Bioeng Biotechnol 2021; 8:622220. [PMID: 33585421 PMCID: PMC7874157 DOI: 10.3389/fbioe.2020.622220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022] Open
Abstract
Globally, increasing mortality from cardiovascular disease has become a problem in recent years. Vascular replacement has been used as a treatment for these diseases, but with blood vessels <6 mm in diameter, existing vascular grafts made of synthetic polymers can be occluded by thrombus formation or intimal hyperplasia. Therefore, the development of new artificial vascular grafts is desirable. In this study, we developed an elastin (EL)-silk fibroin (SF) double-raschel knitted vascular graft 1.5 mm in diameter. Water-soluble EL was prepared from insoluble EL by hydrolysis with oxalic acid. Compared to SF, EL was less likely to adhere to platelets, while vascular endothelial cells were three times more likely to adhere. SF artificial blood vessels densely packed with porous EL were fabricated, and these prevented the leakage of blood from the graft during implantation, while the migration of cells after implantation was promoted. Several kinds of 13C solid-state NMR spectra were observed with the EL-SF grafts in dry and hydrated states. It was noted that the EL molecules in the graft had very high mobility in the hydrated state. The EL-SF grafts were implanted into the abdominal aorta of rats to evaluate their patency and remodeling ability. No adverse reactions, such as bleeding at the time of implantation or disconnection of the sutured ends, were observed in the implanted grafts, and all were patent at the time of extraction. In addition, vascular endothelial cells were present on the graft's luminal surface 2 weeks after implantation. Therefore, we conclude that EL-SF artificial vascular grafts may be useful where small-diameter grafts are required.
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Affiliation(s)
- Takashi Tanaka
- Department of Veterinary Surgery, Tokyo University of Agriculture & Technology, Fuchu, Japan
| | - Yasuyuki Abe
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
| | - Chieh-Jen Cheng
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Ryo Tanaka
- Department of Veterinary Surgery, Tokyo University of Agriculture & Technology, Fuchu, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
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Reichheld SE, Muiznieks LD, Huynh Q, Wang N, Ing C, Miao M, Sitarz EE, Pomès R, Sharpe S, Keeley FW. The evolutionary background and functional consequences of the rs2071307 polymorphism in human tropoelastin. Biopolymers 2020; 112:e23414. [PMID: 33351193 DOI: 10.1002/bip.23414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 01/01/2023]
Abstract
Elastin is a major polymeric protein of the extracellular matrix, providing critical properties of extensibility and elastic recoil. The rs2071307 genomic polymorphism, resulting in the substitution of a serine for a glycine residue in a VPG motif in tropoelastin, has an unusually high minor allele frequency in humans. A consequence of such allelic heterozygosity would be the presence of a heterogeneous elastin polymer in up to 50% of the population, a situation which appears to be unique to Homo sapiens. VPG motifs are extremely common in hydrophobic domains of tropoelastins and are the sites of transient β-turns that are essential for maintaining the conformational flexibility required for its function as an entropic elastomer. Earlier data demonstrated that single amino acid substitutions in tropoelastin can have functional consequences for polymeric elastin, particularly when present in mixed polymers. Here, using NMR and molecular dynamics approaches, we show the rs2071307 polymorphism reduces local propensity for β-turn formation, with a consequent increase in polypeptide hydration and an expansion of the conformational ensemble manifested as an increased hydrodynamic radius, radius of gyration and asphericity. Furthermore, this substitution affects functional properties of polymeric elastin, particularly in heterogeneous polymers mimicking allelic heterozygosity. We discuss whether such effects, together with the unusually high minor allele frequency of the polymorphism, could imply some some evolutionary advantage for the heterozygous state.
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Affiliation(s)
- Sean E Reichheld
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Lisa D Muiznieks
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Elvesys Microfluidics Innovation Center, 172 rue de Charonne, 75011, Paris, France
| | - Quang Huynh
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Nick Wang
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,135 W 52nd St. Apt 20A, 10019-7691, New York, New York, USA
| | - Christopher Ing
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,ProteinQure, Suite 304, 119 Spadina Avenue, M5V2L1, Toronto, Ontario, Canada
| | - Ming Miao
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Eva E Sitarz
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA
| | - Régis Pomès
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Simon Sharpe
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Fred W Keeley
- Molecular Medicine Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, USA.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Djajamuliadi J, Ohgo K, Kumashiro KK. A Two-State Model Describes the Temperature-Dependent Conformational Equilibrium in the Alanine-Rich Domains in Elastin. J Phys Chem B 2020; 124:9017-9028. [PMID: 32936634 DOI: 10.1021/acs.jpcb.0c06811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Elastin is the insoluble elastomeric protein that provides extensibility and resilience to vertebrate tissues. Limited high-resolution structural data for elastin are notably complex. To access this information, this protein is considered in the simplified context of its two general domain types, that is, hydrophobic (HP) and crosslinking (CL). The question of elastin's structure-function has directed the focus of nearly all previous studies in the literature to the unique repeating sequences characteristic of this protein, found primarily in the HP domains. The CL domains were assumed to play a very limited role in biological elasticity due in part to the significant α-helical character that was (incorrectly) predicted for these regions. In this study, the conformational heterogeneity of alanines in native elastin's CL domains is examined in the context of helix-coil transition theory (HCTT) using solid-state nuclear magnetic resonance (SSNMR) spectroscopy in tandem with strategic isotopic labeling. Helix and coil populations are observed at all temperatures, but the former increases significantly at lower temperatures. Below the glass transition temperature (Tg), two major populations of alanines in the CL regions are resolved by two-dimensional SSNMR; one-dimensional methods are used for characterization in nativelike conditions. The spectra of 13CO-Ala in the CL regions are simulated using an HCTT-based statistical mechanical representation. Below Tg, longer segments with significant helical probabilities are consistent with the experimental data. At higher temperatures, the SSNMR lineshapes are best fit with a distribution of shorter (Ala)n segments, most in random coil. These results are used to refine a structure-function model for elastin in the context of HCTT, redirecting attention to the CL domains and their role in elasticity.
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Affiliation(s)
- Jhonsen Djajamuliadi
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kosuke Ohgo
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kristin K Kumashiro
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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Dabalos CL, Ohgo K, Kumashiro KK. Detection of Labile Conformations of Elastin’s Prolines by Solid-State Nuclear Magnetic Resonance and Fourier Transform Infrared Techniques. Biochemistry 2019; 58:3848-3860. [DOI: 10.1021/acs.biochem.9b00414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Chester L. Dabalos
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kosuke Ohgo
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kristin K. Kumashiro
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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Ohgo K, Kumashiro KK. Efficient and accurate determination of 13C T 1 and T 1ρ relaxation time constants of high-mobility polymers from limited-resolution spectra with optimized pulse sequences and data fitting. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 297:161-171. [PMID: 30439590 DOI: 10.1016/j.jmr.2018.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 06/09/2023]
Abstract
The pulse sequences for the measurement of 13C T1 and T1ρ relaxation time constants in soft organic solids were modified to include steady-state nuclear Overhauser enhancement with direct polarization (ssNOE/DP). The increased signal intensities with ssNOE are particularly well-suited for highly mobile and structurally heterogeneous polymers and proteins like elastin. The phase cycling of these experiments was modified to yield datasets that require less time, with more accurate results. The "3D-fitting process" was developed and then optimized for natural-abundance 13C spectra of elastin, with its characteristic and significant overlap. A comparison of 3D-fitting with the similarly purposed SPORT (Geppi and Forte, 1999) illustrates that the former is more robust, with smaller uncertainty values and higher precision.
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Affiliation(s)
- Kosuke Ohgo
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, HI 96822, USA.
| | - Kristin K Kumashiro
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, HI 96822, USA
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