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Huang Y, Lan J, Wu C, Zhang R, Zheng H, Fan S, Xu F. Stability of collagen heterotrimer with same charge pattern and different charged residue identities. Biophys J 2023; 122:2686-2695. [PMID: 37226442 PMCID: PMC10397569 DOI: 10.1016/j.bpj.2023.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 03/20/2023] [Accepted: 05/11/2023] [Indexed: 05/26/2023] Open
Abstract
Salt bridges are important factors in maintaining the stability of proteins, and their contribution to protein folding has received much attention. Although the interaction energies, or stabilizing contributions, of individual salt bridges have been measured in various proteins, a systematic assessment of various types of salt bridges in a relatively uniform environment is still a valuable analysis. Here, we used a collagen heterotrimer as a host-guest platform to construct 48 heterotrimers with the same charge pattern. A variety of salt bridges were formed between the oppositely charged residues Lys, Arg, Asp, and Glu. The melting temperature (Tm) of the heterotrimers was measured with circular dichroism. The atomic structures of 10 salt bridges were shown in three x-ray crystals of heterotrimer. Molecular dynamics simulation based on the crystal structures indicated that strong, intermediate, and weak salt bridges have distinctive N-O distances. A linear regression model was used to predict the stability of heterotrimers with high accuracy (R2 = 0.93). We developed an online database to help readers understand how a salt bridge stabilizes collagen. This work will help us better understand the stabilizing mechanism of salt bridges in collagen folding and provide a new strategy to design collagen heterotrimers.
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Affiliation(s)
- Yujie Huang
- Ministry of Education Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Jun Lan
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Chao Wu
- Ministry of Education Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ruixue Zhang
- Ministry of Education Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hongning Zheng
- Ministry of Education Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China.
| | - Shilong Fan
- Ministry of Education Key Laboratory of Protein Sciences, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
| | - Fei Xu
- Ministry of Education Key Laboratory of Industrial Biotechnology, School of Biotechnology, Jiangnan University, Wuxi, China.
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2
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Buck B, Nguyen J, Porter S, Ben-Zeev D, Reger GM. FOCUS mHealth Intervention for Veterans With Serious Mental Illness in an Outpatient Department of Veterans Affairs Setting: Feasibility, Acceptability, and Usability Study. JMIR Ment Health 2022; 9:e26049. [PMID: 35089151 PMCID: PMC8838564 DOI: 10.2196/26049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/15/2021] [Accepted: 10/04/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Veterans with serious mental illnesses (SMIs) face barriers to accessing in-person evidence-based interventions that improve illness management. Mobile health (mHealth) has been demonstrated to be feasible, acceptable, effective, and engaging among individuals with SMIs in community mental health settings. mHealth for SMIs has not been tested within the Department of Veterans Affairs (VA). OBJECTIVE This study examines the feasibility, acceptability, and preliminary effectiveness of an mHealth intervention for SMI in the context of VA outpatient care. METHODS A total of 17 veterans with SMIs were enrolled in a 1-month pilot trial of FOCUS, a smartphone-based self-management intervention for SMI. At baseline and posttest, they completed measures examining symptoms and functional recovery. The participants provided qualitative feedback related to the usability and acceptability of the intervention. RESULTS Veterans completed on an average of 85.0 (SD 96.1) interactions with FOCUS over the 1-month intervention period. They reported high satisfaction, usability, and acceptability, with nearly all participants (16/17, 94%) reporting that they would recommend the intervention to a fellow veteran. Clinicians consistently reported finding mHealth-related updates useful for informing their care. Qualitative feedback indicated that veterans thought mHealth complemented their existing VA services well and described potential opportunities to adapt FOCUS to specific subpopulations (eg, combat veterans) as well as specific delivery modalities (eg, groups). In the 1-month period, the participants experienced small improvements in self-assessed recovery, auditory hallucinations, and quality of life. CONCLUSIONS The FOCUS mHealth intervention is feasible, acceptable, and usable among veterans. Future work should develop and examine VA-specific implementation approaches of FOCUS for this population.
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Affiliation(s)
- Benjamin Buck
- Behavioral Research in Technology and Engineering (BRiTE) Center, Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States
| | - Janelle Nguyen
- VA Puget Sound Healthcare System, Seattle, WA, United States
| | - Shelan Porter
- VA Puget Sound Healthcare System, Seattle, WA, United States
| | - Dror Ben-Zeev
- Behavioral Research in Technology and Engineering (BRiTE) Center, Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States
| | - Greg M Reger
- Behavioral Research in Technology and Engineering (BRiTE) Center, Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, United States.,VA Puget Sound Healthcare System, Seattle, WA, United States
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3
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Yao ZF, Hsieh S. Age Differences of the Hierarchical Cognitive Control and the Frontal Rostro-Caudal Functional Brain Activation. Cereb Cortex 2021; 32:2797-2815. [PMID: 34727188 PMCID: PMC9247418 DOI: 10.1093/cercor/bhab382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 11/15/2022] Open
Abstract
Age-related differences in the functional hierarchical organization of the frontal lobe remain unclear. We adopted task-related functional magnetic resonance imaging (fMRI) to investigate age differences in the functional hierarchical organization of the frontal lobe. Behavioral results report both reaction time and efficiency declined as the levels of abstraction increased in the selection of a set of stimulus–response mappings in older adults compared with young adults. fMRI findings suggest trends of the hierarchical organization along the rostro–caudal axis in both groups, and brain–behavior correlation further suggests neural dedifferentiation in older adults when performing at the highest level of control demands experiment. Behavioral performances and age difference overactivations at the highest level of control demands were both associated with working memory capacity, suggesting the working memory capacity is important for processing the highest task demands. Region-of-interest analysis revealed age differences in brain overactivation and common activation across experiments in the primary motor cortex, parietal lobule, and the fusiform gyrus may serve as shared mechanisms underlying tasks that are required for the selection of stimulus–response mapping sets. Overall, older adults reflect maladaptive overactivation in task-irrelevant regions that are detrimental to performance with the highest control demands.
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Affiliation(s)
- Zai-Fu Yao
- Brain and Cognition, Psychology Research Institute, University of Amsterdam, 1001 NK Amsterdam, The Netherlands.,Graduate Institute of Sports Training, College of Kinesiology, Tianmu Campus, University of Taipei, Taipei City 11153, Taiwan
| | - Shulan Hsieh
- Department of Psychology, College of Social Sciences, National Cheng Kung University, Tainan City 70101, Taiwan.,Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan City 70101, Taiwan.,Department of Public Health, College of Medicine, National Cheng Kung University, Tainan City 70101, Taiwan
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4
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Snyder A, Sheridan C, Tanner A, Bickart K, Sullan M, Craske M, Choe M, Babikian T, Giza C, Asarnow R. Cardiorespiratory Functioning in Youth with Persistent Post-Concussion Symptoms: A Pilot Study. J Clin Med 2021; 10:561. [PMID: 33546148 PMCID: PMC7913264 DOI: 10.3390/jcm10040561] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/22/2021] [Accepted: 01/30/2021] [Indexed: 12/15/2022] Open
Abstract
Dysregulation of the autonomic nervous system (ANS) may play an important role in the development and maintenance of persistent post-concussive symptoms (PPCS). Post-injury breathing dysfunction, which is influenced by the ANS, has not been well-studied in youth. This study evaluated cardiorespiratory functioning at baseline in youth patients with PPCS and examined the relationship of cardiorespiratory variables with neurobehavioral outcomes. Participants were between the ages of 13-25 in two groups: (1) Patients with PPCS (concussion within the past 2-16 months; n = 13) and (2) non-injured controls (n = 12). Capnometry was used to obtain end-tidal CO2 (EtCO2), oxygen saturation (SaO2), respiration rate (RR), and pulse rate (PR) at seated rest. PPCS participants exhibited a reduced mean value of EtCO2 in exhaled breath (M = 36.3 mmHg, SD = 2.86 mmHg) and an altered inter-correlation between EtCO2 and RR compared to controls. Neurobehavioral outcomes including depression, severity of self-reported concussion symptoms, cognitive catastrophizing, and psychomotor processing speed were correlated with cardiorespiratory variables when the groups were combined. Overall, results from this study suggest that breathing dynamics may be altered in youth with PPCS and that cardiorespiratory outcomes could be related to a dimension of neurobehavioral outcomes associated with poorer recovery from concussion.
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Affiliation(s)
- Aliyah Snyder
- Department of Psychiatry, University of California, Los Angeles, CA 90095, USA; (T.B.); (R.A.)
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
| | - Christopher Sheridan
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC 27101, USA
| | - Alexandra Tanner
- Department of Psychology, University of California, Los Angeles, CA 90095, USA; (A.T.); (M.C.)
| | - Kevin Bickart
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
- Departments of Neurology and Neuropsychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Molly Sullan
- Department of Psychiatry, Psychology Service, University of California, San Diego, CA 92093, USA;
- VA San Diego Healthcare System, San Diego, CA 92161, USA
| | - Michelle Craske
- Department of Psychology, University of California, Los Angeles, CA 90095, USA; (A.T.); (M.C.)
| | - Meeryo Choe
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
- UCLA Mattel Children’s Hospital, Los Angeles, CA 90095, USA
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Talin Babikian
- Department of Psychiatry, University of California, Los Angeles, CA 90095, USA; (T.B.); (R.A.)
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
| | - Christopher Giza
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
- UCLA Mattel Children’s Hospital, Los Angeles, CA 90095, USA
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Robert Asarnow
- Department of Psychiatry, University of California, Los Angeles, CA 90095, USA; (T.B.); (R.A.)
- UCLA Steve Tisch BrainSPORT Program, Los Angeles, CA 90095, USA; (C.S.); (K.B.); (M.C.); (C.G.)
- Department of Psychology, University of California, Los Angeles, CA 90095, USA; (A.T.); (M.C.)
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5
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Zhang Z, Liu J, Gao W, Sun L, Li Z. Action of silicic acid derived from sodium silicate precursor toward improving performances of porous gelatin membrane. J Appl Polym Sci 2020. [DOI: 10.1002/app.48912] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zetian Zhang
- National Engineering Laboratory for Clean Technology of Leather ManufactureSichuan University Chengdu China
- Key Laboratory of Leather Chemistry and Engineering of Ministry of EducationSichuan University Chengdu China
| | - Jun Liu
- College of Chemistry and Environmental Protection EngineeringSouthwest Minzu University Chengdu China
| | - Wenwei Gao
- National Engineering Laboratory for Clean Technology of Leather ManufactureSichuan University Chengdu China
- Key Laboratory of Leather Chemistry and Engineering of Ministry of EducationSichuan University Chengdu China
| | - Liying Sun
- National Engineering Laboratory for Clean Technology of Leather ManufactureSichuan University Chengdu China
- Key Laboratory of Leather Chemistry and Engineering of Ministry of EducationSichuan University Chengdu China
| | - Zhengjun Li
- National Engineering Laboratory for Clean Technology of Leather ManufactureSichuan University Chengdu China
- Key Laboratory of Leather Chemistry and Engineering of Ministry of EducationSichuan University Chengdu China
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Beltran Serrano G, Rodrigues LP, Schein B, Souza A, Torres ILS, da Conceição Antunes L, Fregni F, Caumo W. Comparison of Hypnotic Suggestion and Transcranial Direct-Current Stimulation Effects on Pain Perception and the Descending Pain Modulating System: A Crossover Randomized Clinical Trial. Front Neurosci 2019; 13:662. [PMID: 31297046 PMCID: PMC6608544 DOI: 10.3389/fnins.2019.00662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/07/2019] [Indexed: 01/09/2023] Open
Abstract
Objectives: This paper aims to determine if hypnotic analgesia suggestion and transcranial direct-current stimulation (tDCS) have a differential effect on pain perception. We hypothesized that transcranial direct-current stimulation would be more effective than hypnotic analgesia suggestion at changing the descending pain modulating system, whereas the hypnotic suggestion would have a greater effect in quantitative sensory testing. Design: This is a randomized, double blind and crossover trial. Settings: All stages of this clinical trial were performed at the Laboratory of Pain and Neuromodulation of the Hospital de Clínicas de Porto Alegre. Subjects: Were included 24 healthy females aged from 18 to 45 years old, with a high susceptibility to hypnosis, according to the Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C (15). Methods: The subjects received a random and crossover transcranial direct-current stimulation over the dorsolateral prefrontal cortex (2 mA for 20 min) and hypnotic analgesia (20 min). Results: Only hypnotic suggestion produced changes that are statistically significant from pre- to post-intervention in the following outcomes measures: heat pain threshold, heat pain tolerance, cold pressure test, and serum brain-derivate-neurotrophic-factor. The analysis showed a significant main effect for treatment (F = 4.32; P = 0.04) when we compared the delta-(Δ) of conditioned pain modulation task between the transcranial direct-current stimulation and hypnotic suggestion groups. Also, the change in the brain-derivate-neurotrophic-factor was positively correlated with the conditioned pain modulation task. Conclusion: The results confirm a differential effect between hypnotic suggestion and transcranial direct-current stimulation on the pain measures. They suggest that the impact of the interventions has differential neural mechanisms, since the hypnotic suggestion improved pain perception, whereas the transcranial direct-current stimulation increased inhibition of the descending pain modulating system. Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03744897. Perspective: These findings highlight the effect of hypnotic suggestion on contra-regulating mechanisms involved in pain perception, while the transcranial direct-current stimulation increased inhibition of the descending pain modulating system. They could help clinicians comprehend the mechanisms involved in hypnotic analgesia and transcranial direct-current stimulation and thus may contribute to pain and disability management.
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Affiliation(s)
- Gerardo Beltran Serrano
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Pain and Palliative Care Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Psychology Department, Universidad Católica de Cuenca, Cuenca, Ecuador
| | - Laura Pooch Rodrigues
- Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Bruno Schein
- Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Andressa Souza
- Department of Nutrition, Health Science Center, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Iraci L S Torres
- Postgraduate Program in Health and Human Development, La Salle University, Canoas, Brazil
| | - Luciana da Conceição Antunes
- Department of Nutrition, Health Science Center, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Felipe Fregni
- Berenson-Allen Center for Noninvasive Brain Stimulation, Harvard Medical School, Boston, MA, United States.,Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Wolnei Caumo
- Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Pain and Palliative Care Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Laboratory of Pain and Neuromodulation, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Department of Pharmacology, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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7
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Morozova S, Muthukumar M. Electrostatic effects in collagen fibril formation. J Chem Phys 2018; 149:163333. [PMID: 30384716 DOI: 10.1063/1.5036526] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using light scattering and Atomic Force Microscopy techniques, we have studied the kinetics and equilibrium scattering intensity of collagen association, which is pertinent to the vitreous of the human eye. Specifically, we have characterized fibrillization dependence on pH, temperature, and ionic strength. At higher and lower pH, collagen triple helices remain stable in solution without fibrillization. At physiological pH, fibrillization occurs and the fibril growth is slowed upon either an increase in ionic strength or a decrease in temperature. The total light scattering with respect to ionic strength is non-monotonic in these conditions as a result of a competing dependence of fibril concentration and size on ionic strength. Fibril concentration is the highest at lower ionic strengths and rapidly decays for higher ionic strengths. On the other hand, fibril size is larger in solutions with higher ionic strength. We present a theoretical model, based on dipolar interactions in solutions, to describe the observed electrostatic nature of collagen assembly. At extreme pH values, either very low or very high, collagen triple helices carry a large net charge of the same sign preventing their assembly into fibrils. At intermediate pH values, fluctuations in the charge distribution of the collagen triple helices around roughly zero net charge lead to fibrillization. The growth kinetics of fibrils in this regime can be adequately described by dipolar interactions arising from charge fluctuations.
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Affiliation(s)
- Svetlana Morozova
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Murugappan Muthukumar
- Department of Polymer Science and Engineering, University of Massachusetts, Amherst, Massachusetts 01003, USA
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8
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Niu LN, Jee SE, Jiao K, Tonggu L, Li M, Wang L, Yang YD, Bian JH, Breschi L, Jang SS, Chen JH, Pashley DH, Tay FR. Collagen intrafibrillar mineralization as a result of the balance between osmotic equilibrium and electroneutrality. NATURE MATERIALS 2017; 16:370-378. [PMID: 27820813 PMCID: PMC5321866 DOI: 10.1038/nmat4789] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/28/2016] [Indexed: 05/20/2023]
Abstract
Mineralization of fibrillar collagen with biomimetic process-directing agents has enabled scientists to gain insight into the potential mechanisms involved in intrafibrillar mineralization. Here, by using polycation- and polyanion-directed intrafibrillar mineralization, we challenge the popular paradigm that electrostatic attraction is solely responsible for polyelectrolyte-directed intrafibrillar mineralization. As there is no difference when a polycationic or a polyanionic electrolyte is used to direct collagen mineralization, we argue that additional types of long-range non-electrostatic interaction are responsible for intrafibrillar mineralization. Molecular dynamics simulations of collagen structures in the presence of extrafibrillar polyelectrolytes show that the outward movement of ions and intrafibrillar water through the collagen surface occurs irrespective of the charges of polyelectrolytes, resulting in the experimentally verifiable contraction of the collagen structures. The need to balance electroneutrality and osmotic equilibrium simultaneously to establish Gibbs-Donnan equilibrium in a polyelectrolyte-directed mineralization system establishes a new model for collagen intrafibrillar mineralization that supplements existing collagen mineralization mechanisms.
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Affiliation(s)
- Li-na Niu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, China
| | - Sang Eun Jee
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Kai Jiao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, China
| | - Lige Tonggu
- Department of Biological Structure, University of Washington, Seattle, Washington, USA
| | - Mo Li
- Department of Biological Structure, University of Washington, Seattle, Washington, USA
| | - Liguo Wang
- Department of Biological Structure, University of Washington, Seattle, Washington, USA
| | - Yao-dong Yang
- Frontier Institute of Science and Technology, State Key Laboratory for Mechanical behavior of Materials, Xi’an Jiaotong University, Xi’an, China
| | - Ji-hong Bian
- Frontier Institute of Science and Technology, State Key Laboratory for Mechanical behavior of Materials, Xi’an Jiaotong University, Xi’an, China
| | - Lorenzo Breschi
- Department of Biomedical and Neuromotor Sciences, DIBINEM, University of Bologna, Bologna, Italy
| | - Seung Soon Jang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Ji-hua Chen
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, China
| | - David H. Pashley
- The Dental College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Franklin R. Tay
- The Dental College of Georgia, Augusta University, Augusta, Georgia, USA
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9
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Chemical functionalization and stabilization of type I collagen with organic tanning agents. KOREAN J CHEM ENG 2014. [DOI: 10.1007/s11814-014-0197-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Li ST. Biologic Biomaterials. Biomaterials 2012. [DOI: 10.1201/b13687-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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12
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Boudko SP, Engel J, Okuyama K, Mizuno K, Bächinger HP, Schumacher MA. Crystal structure of human type III collagen Gly991-Gly1032 cystine knot-containing peptide shows both 7/2 and 10/3 triple helical symmetries. J Biol Chem 2008; 283:32580-9. [PMID: 18805790 DOI: 10.1074/jbc.m805394200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Type III collagen is a critical collagen that comprises extensible connective tissue such as skin, lung, and the vascular system. Mutations in the type III collagen gene, COL3A1, are associated with the most severe forms of Ehlers-Danlos syndrome. A characteristic feature of type III collagen is the presence of a stabilizing C-terminal cystine knot. Crystal structures of collagen triple helices reported so far contain artificial sequences like (Gly-Pro-Pro)(n) or (Gly-Pro-Hyp)(n). To gain insight into the structural properties exhibited by the natural type III collagen triple helix, we synthesized, crystallized, and determined the structure of a 12-triplet repeating peptide containing the natural type III collagen sequence from residues 991 to 1032 including the C-terminal cystine knot region, to 2.3A resolution. This represents the longest collagen triple helical structure determined to date with a native sequence. Strikingly, the Gly(991)-Gly(1032) structure reveals that the central non-imino acid-containing region adopts 10/3 superhelical properties, whereas the imino acid rich N- and C-terminal regions adhere to a 7/2 superhelical conformation. The structure is consistent with two models for the cystine knot; however, the poor density for the majority of this region suggests that multiple conformations may be adopted. The structure shows that the multiple non-imino acids make several types of direct intrahelical as well as interhelical contacts. The looser superhelical structure of the non-imino acid region of collagen triple helices combined with the extra contacts afforded by ionic and polar residues likely play a role in fibrillar assembly and interactions with other extracellular components.
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Affiliation(s)
- Sergei P Boudko
- Research Department, Shriners Hospital for Children, Portland, Oregon 97239, USA
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13
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de Gregorio GG, López-Cabarcos E, Castro R. Study of poly(lactic-co-glycolic acid) interactions with collagen. Eur Polym J 2005. [DOI: 10.1016/j.eurpolymj.2005.04.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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15
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Kramer RZ, Venugopal MG, Bella J, Mayville P, Brodsky B, Berman HM. Staggered molecular packing in crystals of a collagen-like peptide with a single charged pair. J Mol Biol 2000; 301:1191-205. [PMID: 10966815 DOI: 10.1006/jmbi.2000.4017] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The crystal structure of the triple-helical peptide, (Pro-Hyp-Gly)(4)-Glu-Lys-Gly-(Pro-Hyp-Gly)(5) has been determined to 1.75 A resolution. This peptide was designed to examine the effect of a pair of adjacent, oppositely charged residues on collagen triple-helical conformation and intermolecular interactions. The molecular conformation (a 7(5) triple helix) and hydrogen bonding schemes are similar to those previously reported for collagen triple helices and provides a second instance of water mediated N--H . . . O==C interchain hydrogen bonds for the amide group of the residue following Gly. Although stereochemically capable of forming intramolecular or intermolecular ion pairs, the lysine and glutamic acid side-chains instead display direct interactions with carbonyl groups and hydroxyproline hydroxyl groups or interactions mediated by water molecules. Solution studies on the EKG peptide indicate stabilization at neutral pH values, where both Glu and Lys are ionized, but suggest that this occurs because of the effects of ionization on the individual residues, rather than ion pair formation. The EKG structure suggests a molecular mechanism for such stabilization through indirect hydrogen bonding. The molecular packing in the crystal includes an axial stagger between molecules, reminiscent of that observed in D-periodic collagen fibrils. The presence of a Glu-Lys-Gly triplet in the middle of the sequence appears to mediate this staggered molecular packing through its indirect water-mediated interactions with backbone C==O groups and side chains.
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Affiliation(s)
- R Z Kramer
- Department of Chemistry, Rutgers University, 610 Taylor Rd, Piscataway, NJ, 08854-8087, USA
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16
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Wallis R, Drickamer K. Molecular determinants of oligomer formation and complement fixation in mannose-binding proteins. J Biol Chem 1999; 274:3580-9. [PMID: 9920905 DOI: 10.1074/jbc.274.6.3580] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rat serum mannose-binding protein (MBP-A) functions as part of the innate immune system by targetting complement toward potentially pathogenic microorganisms. In order to examine the molecular basis for complement activation, rat MBP-A has been overproduced in Chinese hamster ovary cells. Recombinant protein is post-translationally modified in the same way as the native lectin. Hydrodynamic studies indicate that MBP-A consists predominantly of covalent oligomers containing one to four copies of a subunit that comprises a trimer of polypeptides. These oligomers are non-interconverting and do not assemble into higher order structures at concentrations in excess of those normally found in serum. Disulfide bonds formed between cysteine residues at the N-terminal end of the collagen-like domain link polypeptides to form covalent oligomers. Analysis of wild-type MBP-A and MBP-A containing the substitution Cys6 --> Ser suggests that polypeptides within each trimeric structural unit are mostly linked by disulfide bonds between cysteine residues at positions 13 and 18 arranged in an asymmetrical configuration. Disulfide bonds involving Cys6 connect polypeptides within separate trimers. Analysis of chimeras between MBP-A and rat liver MBP (MBP-C) indicates that residues within the N-terminal region of the collagenous domain and the cysteine-rich domain of MBP-A enable assembly of trimers into higher order oligomers. The activity of MBP-A in a hemolytic complement fixation assay using mannan-coated sheep erythrocytes was approximately 20-fold greater than the activity of MBP-C. Analysis of the MBP chimeras and isolated oligomers of MBP-A reveals that the larger oligomers are more efficient at complement activation. These data indicate that the overall complement fixing activity of MBP-A is a function of the individual molecular activities of oligomers and their relative abundance within the serum.
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Affiliation(s)
- R Wallis
- Glycobiology Institute, Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
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Design, synthesis and conformations of novel triple helical collagen mimetic structures. J CHEM SCI 1999. [DOI: 10.1007/bf02869894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Chan VC, Ramshaw JA, Kirkpatrick A, Beck K, Brodsky B. Positional preferences of ionizable residues in Gly-X-Y triplets of the collagen triple-helix. J Biol Chem 1997; 272:31441-6. [PMID: 9395477 DOI: 10.1074/jbc.272.50.31441] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Collagens contain a high amount of charged residues involved in triple-helix stability, fibril formation, and ligand binding. The contribution of charged residues to stability was analyzed utilizing a host-guest peptide system with a single Gly-X-Y triplet embedded within Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gly-NH2. The ionizable residues Arg, Lys, Glu, and Asp were incorporated into the X position of Gly-X-Hyp; in the Y position of Gly-Pro-Y; or as pairs of oppositely charged residues occupying X and Y positions. The Gly-X-Hyp peptides had similar thermal stabilities, only marginally less stable than Gly-Pro-Hyp, whereas Gly-Pro-Y peptides showed a wide thermal stability range (Tm = 30-45 degrees C). The stability of peptides with oppositely charged residues in the X and Y positions appears to reflect simple additivity of the individual residues, except when X is occupied by a basic residue and Y = Asp. The side chains of Glu, Lys, and Arg have the potential to form hydrogen bonds with available peptide backbone carbonyl groups within the triple-helix, whereas the shorter Asp side chain does not. This may relate to the unique involvement of Asp residues in energetically favorable ion pair formation. These studies clarify the dependence of triple-helix stability on the identity, position, and ionization state of charged residues.
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Affiliation(s)
- V C Chan
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, New Jersey 08854-5636, USA
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Katz EP, David CW. Unique side-chain conformation encoding for chirality and azimuthal orientation in the molecular packing of skin collagen. J Mol Biol 1992; 228:963-9. [PMID: 1469727 DOI: 10.1016/0022-2836(92)90878-n] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We used molecular mechanics to study the role of gly X-Y+ sequences, where X- was Asp or Glu and Y+ was Lys or Arg, in the molecular packing of type I collagen. In the minimal energy conformation of a triply stranded molecule having a coiled-coil configuration, the side-chains of these sequences segregated into two oppositely charged groupings of the forms X-Y+X- and Y+X-Y+. Groupings having the same net charge were clustered along two complementary azimuthal edges of the molecule. Intermolecular interactions, through these oppositely charged edges, align the molecules appropriately for the formation of the HHL crosslink of skin. This alignment also can account for the axial periodicity and chiral appearance of skin collagen fibrils.
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Affiliation(s)
- E P Katz
- Department of BioStructure and Function, University of Connecticut Health Center, Farmington 06030-3705
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Wallace DG. The relative contribution of electrostatic interactions to stabilization of collagen fibrils. Biopolymers 1990; 29:1015-26. [PMID: 2369612 DOI: 10.1002/bip.360290613] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Electrostatic energies of interaction between type I collagen molecules were calculated, using models developed by Timasheff and Hill. These energies, along with a contribution from hydrophobic forces, were then incorporated into an equation due to Flory that described phase equilibria of rod-like polymers. The Flory formalism in turn permitted a calculation of the overall free energy of fibril formation (delta Ff), and an assessment of the relative contribution of electrostatic and hydrophobic forces to delta Ff. Lastly, delta Ff was used in a nucleation-growth model relating halftimes of fibril formation (t1/2) to ionic strength (I) and temperature. Because the theory provided no basis for setting absolute levels of the energetic contributions, five parameters in the model had to be derived from experimental data. Based on the fit of theory to experimental results both for intact and pepsinized collagen, it was found that very low electrostatic energies (about -1 kcal/mole per collagen molecule) were sufficient to explain experimental t1/2 vs I relationships. This energy is equivalent to 1 close charge-pair interaction per molecule and appears to be lower than the energy assignable to hydrophobic interactions.
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Affiliation(s)
- D G Wallace
- Celltrix Laboratories, Collagen Corporation, Palo Alto, California 94303
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Abstract
The energy of formation of salt linkages between Arg or Lys with Asp or Glu in a polypeptide chain having the collagen fold have been estimated using the fully empirical energy minimization scheme AMBER. The polypeptide was considered both in an isolated and a hydrated triple helical state. The collagen fold associated with a one-bonded triple helical conformation allows intrachain salt linkages having stabilization energies of 60-100 kcal when the reacting residues are separated by no more than two intervening residues. The amino end of one side chain always approaches the carboxyl end of the other side chain, and simultaneously approaches the carbonyl oxygen of the intervening backbone residue. The salt linkage conformation and the backbone conformation of the isolated collagen fold in vacuo are maintained when the molecules are in a hydrated triple helix. These results are compatible with a fold-forming role for salt linkages, especially in proline poor regions, during collagen polypeptide synthesis, and with the persistence of intrachain salt linkages throughout molecular and fibril assembly.
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Affiliation(s)
- E P Katz
- Department of Biostructure and Function, University of Connecticut Health Center, Farmington 06032
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Miller A, Li ST, Bronner F. Characterization of calcium binding to brush-border membranes from rat duodenum. Biochem J 1982; 208:773-81. [PMID: 7165733 PMCID: PMC1154030 DOI: 10.1042/bj2080773] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The Ca2+-binding properties of isolated brush-border membranes at physiological ionic strength and pH were examined by rapid Millipore filtration. A comprehensive analysis of the binding data suggested the presence of two types of Ca2+-binding sites. The high-affinity sites, Ka = (6.3 +/- 3.3) X 10(5) M-1 (mean +/- S.E.M.), bound 0.8 +/- 0.1 nmol of Ca2+/mg of protein and the low-affinity sites, Ka = (2.8 +/- 0.3) X 10(2) M-1, bound 33 +/- 3.5 nmol of Ca2+/mg of protein. The high-affinity site exhibited a selectivity for Ca2+, since high concentrations of competing bivalent cations were required to inhibit Ca2+ binding. The relative effectiveness of the competing cations (1 and 10 mM) for the high-affinity site was Mn2+ approximately equal to Sr2+ greater than Ba2+ greater than Mg2+. Data from the pH studies, treatment of the membranes with carbodi-imide and extraction of phospholipids with aqueous acetone and NH3 provided evidence that the low-affinity sites were primarily phospholipids and the high-affinity sites were either phosphoprotein or protein with associated phospholipid. Two possible roles for the high-affinity binding sites are suggested. Either high-affinity Ca2+ binding is involved with specific enzyme activities or Ca2+ transport across the luminal membrane occurs via a Ca2+ channel which contains a high-affinity Ca2+-specific binding site that may regulate the intracellular Ca2+ concentration and gating of the channel.
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Bender E, Silver FH, Hayashi K, Trelstad RL. Type I collagen segment long spacing banding patterns. Evidence that the alpha 2 chain is in the reference or A position. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34122-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Silver FH. A molecular model for linear and lateral growth of type I collagen fibrils. COLLAGEN AND RELATED RESEARCH 1982; 2:219-29. [PMID: 7151387 DOI: 10.1016/s0174-173x(82)80016-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A model is proposed for Type I collagen fibrillogenesis in which linear and lateral growth are directed by attractive charged pair interactions. It is suggested that linear growth decreases the rate of rotational motion resulting in an increased rate of lateral collisions. The mechanism of linear aggregation involves interactions between sets of unusual charged pairs located at positions 53, 54 and 56 and positions 990 and 992 as well as in the non-helical ends. These charged pairs attract each other electrostatically as well as form a hydrophobic pocket between the molecules. Lateral growth occurs by attractions between D-staggered, charged pairs which alternate between intra- and interchain states. Interchain interactions lead to lateral association of neighboring molecules and formation of a D-staggered unit containing five trimers. Rotational motion of the triple-helical backbone as well as the ability of charged pairs in their interchain state to interact by several different possible combinations between alpha-chains suggest that lateral packing of collagen molecules into fibrils at least in vitro may not need to be specific.
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Jelinski LW, Torchia DA. Investigation of labeled amino acid side-chain motion in collagen using 13C nuclear magnetic resonance. J Mol Biol 1980; 138:255-72. [PMID: 7411609 DOI: 10.1016/0022-2836(80)90286-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Li ST, Katz EP. On the state of anionic groups of demineralized matrices of bone and dentine. CALCIFIED TISSUE RESEARCH 1977; 22:275-84. [PMID: 321100 DOI: 10.1007/bf02010366] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium-binding and biochemical studies have been applied to characterize the state of the carboxylate and protein-bound phosphate groups in the EDTA-demineralized matrices of rat bone and dentine. The organic phosphate and carboxylate content of demineralized bone is virtually identical to that of purified steer skin collagen whereas demineralized dentine has a significantly higher phosphate and carboxylate content, presumably due to the presence of an acidic non-collagenous phosphoprotein. Two classes of calcium-binding sites can be detected in demineralized bone, demineralized dentine, and purified, reconstituted collagen. The number of strong calcium-binding sites correlates with the number of protein-bound phosphate groups. Depending on the preparative procedure, seven to nine such sites (per collagen molecule) are present in dentine, and one to two in the purified reconstituted collagen and in bone. The binding constant for the dentinal sites (1.1 X 10(4) M-1), however, is 20 times greater than that for bone or reconstituted collagen fibrils from skin. We tentatively conclude that the strong calcium-binding site in bone and reconstituted collagen is of the form protein-PO-4Ca++ whereas in dentine it is of the form protein (formula: see text); the weak binding sites in bone and dentine are of the form protein-COO-Ca++; and that approximately 160 of the 217 carboxylate groups of the collagen molecules of dentine or bone are present as electrostatic linkages of the form protein-COO-+H3N-protein.
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