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Mann K, Cerveau N, Gummich M, Fritz M, Mann M, Jackson DJ. In-depth proteomic analyses of Haliotis laevigata (greenlip abalone) nacre and prismatic organic shell matrix. Proteome Sci 2018; 16:11. [PMID: 29983641 PMCID: PMC6003135 DOI: 10.1186/s12953-018-0139-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/25/2018] [Indexed: 01/12/2023] Open
Abstract
Background The shells of various Haliotis species have served as models of invertebrate biomineralization and physical shell properties for more than 20 years. A focus of this research has been the nacreous inner layer of the shell with its conspicuous arrangement of aragonite platelets, resembling in cross-section a brick-and-mortar wall. In comparison, the outer, less stable, calcitic prismatic layer has received much less attention. One of the first molluscan shell proteins to be characterized at the molecular level was Lustrin A, a component of the nacreous organic matrix of Haliotis rufescens. This was soon followed by the C-type lectin perlucin and the growth factor-binding perlustrin, both isolated from H. laevigata nacre, and the crystal growth-modulating AP7 and AP24, isolated from H. rufescens nacre. Mass spectrometry-based proteomics was subsequently applied to to Haliotis biomineralization research with the analysis of the H. asinina shell matrix and yielded 14 different shell-associated proteins. That study was the most comprehensive for a Haliotis species to date. Methods The shell proteomes of nacre and prismatic layer of the marine gastropod Haliotis laevigata were analyzed combining mass spectrometry-based proteomics and next generation sequencing. Results We identified 297 proteins from the nacreous shell layer and 350 proteins from the prismatic shell layer from the green lip abalone H. laevigata. Considering the overlap between the two sets we identified a total of 448 proteins. Fifty-one nacre proteins and 43 prismatic layer proteins were defined as major proteins based on their abundance at more than 0.2% of the total. The remaining proteins occurred at low abundance and may not play any significant role in shell fabrication. The overlap of major proteins between the two shell layers was 17, amounting to a total of 77 major proteins. Conclusions The H. laevigata shell proteome shares moderate sequence similarity at the protein level with other gastropod, bivalve and more distantly related invertebrate biomineralising proteomes. Features conserved in H. laevigata and other molluscan shell proteomes include short repetitive sequences of low complexity predicted to lack intrinsic three-dimensional structure, and domains such as tyrosinase, chitin-binding, and carbonic anhydrase. This catalogue of H. laevigata shell proteins represents the most comprehensive for a haliotid and should support future efforts to elucidate the molecular mechanisms of shell assembly. Electronic supplementary material The online version of this article (10.1186/s12953-018-0139-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karlheinz Mann
- 1Abteilung Proteomics und Signaltransduktion, Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Nicolas Cerveau
- 2Department of Geobiology, Georg-August University of Göttingen, Goldschmidstr. 3, 37077 Göttingen, Germany
| | - Meike Gummich
- 3Universität Bremen, Institut für Biophysik, Otto Hahn Allee NW1, D-28334 Bremen, Germany
| | - Monika Fritz
- 3Universität Bremen, Institut für Biophysik, Otto Hahn Allee NW1, D-28334 Bremen, Germany
| | - Matthias Mann
- 1Abteilung Proteomics und Signaltransduktion, Max-Planck-Institut für Biochemie, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Daniel J Jackson
- 2Department of Geobiology, Georg-August University of Göttingen, Goldschmidstr. 3, 37077 Göttingen, Germany
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Du YP, Chang HH, Yang SY, Huang SJ, Tsai YJ, Huang JJT, Chan JCC. Study of Binding Interaction between Pif80 Protein Fragment and Aragonite. Sci Rep 2016; 6:30883. [PMID: 27484975 PMCID: PMC4971512 DOI: 10.1038/srep30883] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 07/11/2016] [Indexed: 11/08/2022] Open
Abstract
Pif is a crucial protein for the formation of the nacreous layer in Pinctada fucata. Three non-acidic peptide fragments of the aragonite-binding domain (Pif80) are selected, which contain multiple copies of the repeat sequence DDRK, to study the interaction between non-acidic peptides and aragonite. The polypeptides DDRKDDRKGGK (Pif80-11) and DDRKDDRKGGKDDRKDDRKGGK (Pif80-22) have similar binding affinity to aragonite. Solid-state NMR data indicate that the backbones of Pif80-11 and Pif80-22 peptides bound on aragonite adopt a random-coil conformation. Pif80-11 is a lot more effective than Pif80-22 in promoting the nucleation of aragonite on the substrate of β-chitin. Our results suggest that the structural arrangement at a protein-mineral interface depends on the surface structure of the mineral substrate and the protein sequence. The side chains of the basic residues, which function as anchors to the aragonite surface, have uniform structures. The role of basic residues as anchors in protein-mineral interaction may play an important role in biomineralization.
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Affiliation(s)
- Yuan-Peng Du
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Hsun-Hui Chang
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Sheng-Yu Yang
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Shing-Jong Huang
- Instrumentation Center, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
| | - Yu-Ju Tsai
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei 115, Taiwan
| | - Joseph Jen-Tse Huang
- Institute of Chemistry, Academia Sinica, No. 128, Sec. 2, Academia Road, Nankang, Taipei 115, Taiwan
| | - Jerry Chun Chung Chan
- Department of Chemistry, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 106, Taiwan
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Chang EP, Perovic I, Rao A, Cölfen H, Evans JS. Insect Cell Glycosylation and Its Impact on the Functionality of a Recombinant Intracrystalline Nacre Protein, AP24. Biochemistry 2016; 55:1024-35. [PMID: 26784838 DOI: 10.1021/acs.biochem.5b01186] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The impacts of glycosylation on biomineralization protein function are largely unknown. This is certainly true for the mollusk shell, where glycosylated intracrystalline proteins such as AP24 (Haliotis rufescens) exist but their functions and the role of glycosylation remain elusive. To assess the effect of glycosylation on protein function, we expressed two recombinant variants of AP24: an unglycosylated bacteria-expressed version (rAP24N) and a glycosylated insect cell-expressed version (rAP24G). Our findings indicate that rAP24G is expressed as a single polypeptide containing variations in glycosylation that create microheterogeneity in rAP24G molecular masses. These post-translational modifications incorporate O- and N-glycans and anionic monosialylated and bisialylated, and monosulfated and bisulfated monosaccharides on the protein molecules. AFM and DLS experiments confirm that both rAP24N and rAP24G aggregate to form protein phases, with rAP24N exhibiting a higher degree of aggregation, compared to rAP24G. With regard to functionality, we observe that both recombinant proteins exhibit similar behavior within in vitro calcium carbonate mineralization assays and potentiometric titrations. However, rAP24G modifies crystal growth directions and is a stronger nucleation inhibitor, whereas rAP24N exhibits higher mineral phase stabilization and nanoparticle containment. We believe that the post-translational addition of anionic groups (via sialylation and sulfation), along with modifications to the protein surface topology, may explain the changes in glycosylated rAP24G aggregation and mineralization behavior, relative to rAP24N.
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Affiliation(s)
- Eric P Chang
- Laboratory for Chemical Physics, Division of Basic Sciences and Center for Skeletal Biology, New York University , 345 E. 24th Street, New York, New York 10010, United States
| | - Iva Perovic
- Laboratory for Chemical Physics, Division of Basic Sciences and Center for Skeletal Biology, New York University , 345 E. 24th Street, New York, New York 10010, United States
| | - Ashit Rao
- Department of Chemistry, Physical Chemistry, Universität Konstanz , Universitätstrasse 10, Konstanz D-78457, Germany
| | - Helmut Cölfen
- Department of Chemistry, Physical Chemistry, Universität Konstanz , Universitätstrasse 10, Konstanz D-78457, Germany
| | - John Spencer Evans
- Laboratory for Chemical Physics, Division of Basic Sciences and Center for Skeletal Biology, New York University , 345 E. 24th Street, New York, New York 10010, United States
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4
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Gong H, Yang Y, Pluntke M, Marti O, Majer Z, Sewald N, Volkmer D. Calcium carbonate crystal growth beneath Langmuir monolayers of acidic β-hairpin peptides. Dalton Trans 2014; 43:16857-71. [PMID: 25292256 DOI: 10.1039/c4dt01154f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Four amphiphilic peptides with designed hairpin structure were synthesized and their monolayers were employed as model systems to study biologically inspired calcium carbonate crystallization. Langmuir monolayers of hairpin peptides were investigated by surface pressure area isotherms, surface potential isotherms, Brewster angle microscopy (BAM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. A β-hairpin conformation was found for all peptides at the air-water interface although their packing arrangements seem to be different. Crystallization of calcium carbonate under these peptide monolayers was investigated at different surface pressures and growth times both by in situ optical microscopy, BAM and ex situ investigations such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An amorphous calcium carbonate precursor was found at the initial crystallization stage. The crystallization process occurred in three stages. It starts from the nucleation of amorphous particles being a kinetically controlled process. Crystal nuclei subsequently aggregate to large particles and vaterite crystals start to form inside the amorphous layer, with the monolayer fluidity exerting an important role. The third process includes the re-crystallization of vaterite to calcite, which is thermodynamically controlled by monolayer structural factors including the monolayer flexibility and packing arrangement of the polar headgroups. Thus, the kinetic factors, monolayer fluidity and flexibility as well as structure factors govern the crystal morphology and polymorph distribution simultaneously and synergistically.
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Affiliation(s)
- Haofei Gong
- Institute of Physics, Chair of Solid State and Materials Chemistry, Augsburg University, Universitätsstrasse 1, D-86159 Augsburg, Germany.
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Brown AH, Rodger PM, Evans JS, Walsh TR. Equilibrium Conformational Ensemble of the Intrinsically Disordered Peptide n16N: Linking Subdomain Structures and Function in Nacre. Biomacromolecules 2014; 15:4467-79. [DOI: 10.1021/bm501263s] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Aaron H. Brown
- Institute
for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia
| | | | - John Spencer Evans
- Department
of Craniofacial Biology and Center for Skeletal Sciences, New York University, New York, New York 10010, United States
| | - Tiffany R. Walsh
- Institute
for Frontier Materials, Deakin University, Geelong, VIC 3216, Australia
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Abstract
In nature, mollusk shells have a role in protecting the soft body of the mollusk from predators and from the external environment, and the shells consist mainly of calcium carbonate and small amounts of organic matrices. Organic matrices in mollusk shells are thought to play key roles in shell formation. However, enough information has not been accumulated so far. High toughness and stiffness have been focused on as being adaptable to the development of organic–inorganic hybrid materials. Because mollusks can produce elaborate microstructures containing organic matrices under ambient conditions, the investigation of shell formation is expected to lead to the development of new inorganic–organic hybrid materials for various applications. In this review paper, we summarize the structures of mollusk shells and their process of formation, together with the analysis of various organic matrices related to shell calcification.
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Affiliation(s)
- Michio Suzuki
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hiromichi Nagasawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Amos FF, Ndao M, Ponce CB, Evans JS. A C-RING-like domain participates in protein self-assembly and mineral nucleation. Biochemistry 2011; 50:8880-7. [PMID: 21928802 DOI: 10.1021/bi201346d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
AP7 is a nacre-associated protein of the mollusk shell that forms supramolecular assemblies that nucleate single-crystal aragonite in vitro. AP7 possesses two major sequence regions: a random coil 30-amino acid N-terminal domain (AP7N) and a partially disordered 36-amino acid C-terminal domain (AP7C) that exhibits imperfect sequence homology to the C subclass of the intracellular RING domain family. We report here new findings that implicate the C-RING domain in AP7-mediated supramolecular assembly and single-crystal mineral formation. AP7 protein spontaneously self-assembles over a pH range of 4-9 and is monomeric at pH >9.5. AP7N and AP7C both oligomerize over the pH range of 4-9, with the AP7C sequence closely resembling AP7 in terms of particle morphology and size. In vitro mineralization experiments demonstrate that both AP7N and AP7C form supramolecular assemblies that nucleate single-crystal calcium carbonates. Comparison of previously published nuclear magnetic resonance-based structures of AP7C and AP7N reveals the significant presence of complementary anionic-cationic electrostatic molecular surfaces on AP7C that are not found on AP7N, and this may explain the noted discrepancies between the two domains in terms of self-assembly and single-crystal nucleation. We conclude that the C-RING-like sequence is an important site for AP7 self-association and mineral nucleation, and this represents the first known instance of a RING-like sequence performing these functions within an extracellular protein.
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Affiliation(s)
- Fairland F Amos
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010, USA
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Seker UOS, Ozel T, Demir HV. Peptide-mediated constructs of quantum dot nanocomposites for enzymatic control of nonradiative energy transfer. NANO LETTERS 2011; 11:1530-1539. [PMID: 21428276 DOI: 10.1021/nl104295b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A bottom-up approach for constructing colloidal semiconductor quantum dot (QDot) nanocomposites that facilitate nonradiative Förster-type resonance energy transfer (FRET) using polyelectrolyte peptides was proposed and realized. The electrostatic interaction of these polypeptides with altering chain lengths was probed for thermodynamic, structural, and morphological aspects. The resulting nanocomposite film was successfully cut with the protease by digesting the biomimetic peptide layer upon which the QDot assembly was constructed. The ability to control photoluminescence decay lifetime was demonstrated by proteolytic enzyme activity, opening up new possibilities for biosensor applications.
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9
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Lu W, Zhou D, Freeman JJ, Thalmann I, Ornitz DM, Thalmann R. In vitro effects of recombinant otoconin 90 upon calcite crystal growth. Significance of tertiary structure. Hear Res 2010; 268:172-83. [PMID: 20595020 DOI: 10.1016/j.heares.2010.05.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 05/25/2010] [Accepted: 05/25/2010] [Indexed: 01/27/2023]
Abstract
Otoconia are biomineral particles of microscopic size essential for perception of gravity and maintenance of balance. Millions of older Americans are affected in their mobility, quality of life and in their health by progressive demineralization of otoconia. Currently, no effective means to prevent or counteract this process are available. Because of prohibitive anatomical and biological constraints, otoconial research is lagging far behind other systems such as bone and teeth. We have overcome these obstacles by generating otoconial matrix proteins by recombinant techniques. In the present study, we evaluated the effects of recombinant Otoconin 90 (OC90), the principal soluble matrix protein upon calcite crystal growth patterns in vitro. Our findings highlight multiple effects, including facilitation of nucleation, and inhibition of crystal growth in a concentration-dependent manner. Moreover, OC90 induces morphologic changes characteristic of native otoconia. OC90 is considerably less acidic than the prototypical invertebrate CaCO(3) -associated protein, but is nevertheless an effective modulator of calcite crystal growth. Based on homology modeling of the sPLA2-like domains of OC90, we propose that the lower density of acidic residues of the primary sequence is compensated by formation of major anionic surface clusters upon folding into tertiary conformation.
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Affiliation(s)
- Wenfu Lu
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St Louis, MO 63110, USA.
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10
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Amos FF, Ndao M, Evans JS. Evidence of Mineralization Activity and Supramolecular Assembly by the N-Terminal Sequence of ACCBP, a Biomineralization Protein That Is Homologous to the Acetylcholine Binding Protein Family. Biomacromolecules 2009; 10:3298-305. [DOI: 10.1021/bm900893f] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Fairland F. Amos
- Center for Biomolecular Materials Spectroscopy, Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
| | - Moise Ndao
- Center for Biomolecular Materials Spectroscopy, Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
| | - John Spencer Evans
- Center for Biomolecular Materials Spectroscopy, Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
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11
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Yang M, Mark Rodger P, Harding JH, Stipp S. Molecular dynamics simulations of peptides on calcite surface. MOLECULAR SIMULATION 2009. [DOI: 10.1080/08927020802627399] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Delak K, Collino S, Evans JS. Polyelectrolyte Domains and Intrinsic Disorder within the Prismatic Asprich Protein Family. Biochemistry 2009; 48:3669-77. [DOI: 10.1021/bi900113v] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Katya Delak
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
| | - Sebastiano Collino
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
| | - John Spencer Evans
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
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Amos FF, Evans JS. AP7, a Partially Disordered Pseudo C-RING Protein, Is Capable of Forming Stabilized Aragonite in Vitro. Biochemistry 2009; 48:1332-9. [DOI: 10.1021/bi802148r] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Fairland F. Amos
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
| | - John Spencer Evans
- Laboratory for Chemical Physics, New York University, 345 East 24th Street, New York, New York 10010
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14
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Harding JH, Duffy DM, Sushko ML, Rodger PM, Quigley D, Elliott JA. Computational Techniques at the Organic−Inorganic Interface in Biomineralization. Chem Rev 2008; 108:4823-54. [DOI: 10.1021/cr078278y] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- John H. Harding
- Department of Engineering Materials, University of Sheffield, Sheffield, U.K
| | | | | | | | | | - James A. Elliott
- Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, U.K
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Sommerdijk NAJM, With GD. Biomimetic CaCO3 Mineralization using Designer Molecules and Interfaces. Chem Rev 2008; 108:4499-550. [DOI: 10.1021/cr078259o] [Citation(s) in RCA: 369] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Nico A. J. M. Sommerdijk
- Soft-matter cryoTEM Research Unit and Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Gijsbertus de With
- Soft-matter cryoTEM Research Unit and Laboratory of Materials and Interface Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Evans JS. “Tuning in” to Mollusk Shell Nacre- and Prismatic-Associated Protein Terminal Sequences. Implications for Biomineralization and the Construction of High Performance Inorganic−Organic Composites. Chem Rev 2008; 108:4455-62. [DOI: 10.1021/cr078251e] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- John Spencer Evans
- Laboratory for Chemical Physics, Center for Biomolecular Materials Spectroscopy, New York University, 345 E. 24th Street, Room 1007, New York, New York, 10010
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Collino S, Evans JS. Molecular specifications of a mineral modulation sequence derived from the aragonite-promoting protein n16. Biomacromolecules 2008; 9:1909-18. [PMID: 18558739 DOI: 10.1021/bm8001599] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the nacre layer of the mollusk, proteins play an important role in regulating the morphology and lattice structure of calcium carbonate minerals. However, this process remains elusive due to the fact that we do not understand how protein sequences control the structure and morphology of biominerals. To take us a step further in this direction, we report the molecular structure of a 30 AA N-terminal mineral interactive sequence (n16N) of the aragonite-promoting protein, n16, and contrast these findings to those previously reported for two "calcite-blocker" nacre-associated sequences, AP7N and AP24N. We find that n16N is conformationally labile and adopts a random-coil conformation that possesses short, dispersed extended beta-strand segments that are located at the A1-Y2, K5-Y9, Y11-I14, and D21-N25 sequence blocks. Like AP7N and AP24N, Ca(II) ion interactions with n16N alter chain dynamics and local structure, and n16N is adsorbed onto calcite crystals and cannot easily be displaced via differential washing techniques. Furthermore, all three sequences have planar surface regions that could serve as putative sites for mineral interactions or ion cluster formation. However, what sets n16N apart from AP7N and AP24N are different folding propensities as well as unique molecular surface features and amino acid composition. n16N has a more condensed structure that, in the presence of TFE, folds into a beta-strand. This contrasts with the more open structures of AP7N and AP24N that are induced by TFE to fold into alpha-helices. Mapping of the n16N molecular surface reveals significant cationic regions and diffuse anionic charge, which contrasts with the small anionic "pocket" regions of AP7N/AP24N. Finally, n16N has 50% fewer sites for mineral surface- or ion cluster-associated water interactions compared to AP7N and AP24N. Overall, the structure of n16N is "tuned" to a different function within the in vitro mineralization scheme. The different features found in AP7N, AP24N, and n16N could be exploited for engineering polypeptides that recognize and bind to different surface features of inorganic crystalline solids.
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Affiliation(s)
- Sebastiano Collino
- Laboratory for Chemical Physics, Center for Biomolecular Materials Spectroscopy, New York University, 345 East 24th Street, Room 1007, New York, New York 10010, USA
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Collino S, Kim IW, Evans JS. Identification and structural characterization of an unusual RING-like sequence within an extracellular biomineralization protein, AP7. Biochemistry 2008; 47:3745-55. [PMID: 18298090 DOI: 10.1021/bi701949p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The RING or Really Interesting New Gene represents a family of eukaryotic sequences that bind Zn (II) ions and participate in intracellular processes involving protein-protein interaction. Although found in over 400 different proteins, very little is known regarding the structure-function properties of these domains because of the aggregation problems associated with RING sequences. To augment this data set, we report an unusual 36 AA C-terminal sequence of an extracellular matrix mollusk shell protein, AP7, that exhibits partial homology to the RING family. This Cys, His-containing sequence, termed AP7C, binds Zn (II) and other multivalent ions, but does not utilize a tetracoordinate complexation scheme for binding such as that found in Zn (II) finger polypeptides. Moreover, unlike Zn (II) finger and RING domains, this 36 AA can fold into a relatively stable structure in the absence of Zn (II). This folded structure consists of three short helical segments (A, B, and C), with segments A and B separated by a 4 AA type I beta-turn region and segments B and C separated by a 7 AA loop-like region. Interestingly, the putative RING-like region, -RRPFHECALCYSI-, experiences slow conformational exchange between two structural states in solution, most likely in response to imido ring interconversion at P8 and P21. Poisson-Boltzmann solvation calculations reveal that the AP7C molecular surface possesses a cationic region near its N-terminus, which lies adjacent to the 30 AA mineral modification domain in the AP7 protein. Given that the AP7C sequence does not influence mineralization, it is probable that this cationic pseudo-RING region is utilized by the AP7 protein for other tasks such as protein-protein interaction within the mollusk shell matrix.
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Affiliation(s)
- Sebastiano Collino
- Laboratory for Chemical Physics, Center for Biomolecular Materials Spectroscopy, New York University, 345 E. 24th Street, Room 1007, New York, New York 10010, USA
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Delak K, Collino S, Evans JS. Expected and unexpected effects of amino acid substitutions on polypeptide-directed crystal growth. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:11951-11955. [PMID: 17967039 DOI: 10.1021/la702113x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Nature's use of biomineralization polypeptides to control and modulate the growth of biogenic minerals is an important process that, if properly understood, could have significant implications for designing and creating new inorganic-based materials. Although the sequences for a number of biomineralization proteins exist, very little is known about the participation of specific amino acids in the mineral modulation process. In this letter, we investigate the impact of global Asp --> Asn and Glu --> Gln substitutions on two mollusk shell nacre polypeptides, AP7N and n16N. We find that these global substitutions, which remove all anionic Ca(II) binding sites, abolish the expected in vitro mineralization activities associated with each native polypeptide. In addition, the ability of substituted peptides to form complexes with both Ca(II) and Ca(II) metal ion analogs is also abolished. However, some unexpected effects were noted. First, the Asp --> Asn, Glu --> Gln substituted n16N polypeptide is observed to self-assemble and form biofilms or coatings that appear to mineralize in vitro. Second, both polypeptides are structurally affected by these substitutions, with Asp --> Asn substituted AP7N transforming to an alpha helix and Asp --> Asn, Glu --> Gln substituted n16N transforming to a more unfolded random-coil-like structure. We find that the participation of Asp and Glu residues is crucial to the inherent mineralization activities and conformations of AP7N and n16N polypeptides. Surprisingly, we find that the replacement of anionic residues within biomineralization polypeptides such as n16N still permits mineral modulation, but in a different form that now involves peptide self-association and biofilm formation.
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Affiliation(s)
- Katya Delak
- Laboratory for Chemical Physics, Center for Biomolecular Materials Spectroscopy, New York University, 345 East 24th Street, New York, NY 10010, USA
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