Molecular characterization of the 30-AA N-terminal mineral interaction domain of the biomineralization protein AP7

Il Won Kim, Daniel E. Morse, John Evans

Research output: Contribution to journalArticle

Abstract

The AP7 protein is one of several mollusk shell proteins which are responsible for aragonite polymorph formation and stabilization within the nacre layer of the Pacific red abalone, H. rufescens. Previously, we demonstrated that the 30-AA N-terminal domain of AP7, denoted as AP7-1, exists as an unfolded sequence and possesses the capability of inhibiting calcium carbonate crystal growth in vitro via growth step frustration or interruption. However, very little is known with regard to the interactive capabilities of this sequence with Ca(II) and with calcium carbonates. Using multidisciplinary techniques, we determine that the AP7-1 polypeptide interacts with Ca(II) ions at the -DD- sequence clusters, yet retains its unfolded, conformationally labile structure in the presence of Ca(II) ions. Further, NMR experiments reveal that the extended structured sequence blocks, -GNGM-, -SVRTQG-, and -ISYL, exhibit motional, chemical exchange, and/or backbone geometry perturbations in response to Ca(II) interactions with AP7-1. Solid-state NMR magic angle spinning studies verify that during the course of in vitro calcium carbonate crystal growth, AP7-1 becomes bound to calcite fragments and cannot be entirely displaced from the mineral fragments using competitive Ca(II) washing. Finally, using a scrambled sequence version of the AP7-1 polypeptide, we observe that sequence scrambling does not adversely affect the crystal growth inhibitory activity of AP7-1, suggesting that the amino acid composition of AP7-1 may be more critical to growth step inhibition than the linear ordering of amino acids.

Original languageEnglish (US)
Pages (from-to)11664-11673
Number of pages10
JournalLangmuir
Volume20
Issue number26
DOIs
StatePublished - Dec 21 2004

Fingerprint

Protein Interaction Domains and Motifs
Biomineralization
Calcium Carbonate
calcium carbonates
Calcium carbonate
Crystal growth
Minerals
crystal growth
Polypeptides
polypeptides
minerals
proteins
Proteins
Crystallization
amino acids
Amino acids
mollusks
Nuclear magnetic resonance
fragments
aragonite

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Molecular characterization of the 30-AA N-terminal mineral interaction domain of the biomineralization protein AP7. / Kim, Il Won; Morse, Daniel E.; Evans, John.

In: Langmuir, Vol. 20, No. 26, 21.12.2004, p. 11664-11673.

Research output: Contribution to journalArticle

@article{4c7a7ec2f1fb45e9a632f7b392dea4a7,
title = "Molecular characterization of the 30-AA N-terminal mineral interaction domain of the biomineralization protein AP7",
abstract = "The AP7 protein is one of several mollusk shell proteins which are responsible for aragonite polymorph formation and stabilization within the nacre layer of the Pacific red abalone, H. rufescens. Previously, we demonstrated that the 30-AA N-terminal domain of AP7, denoted as AP7-1, exists as an unfolded sequence and possesses the capability of inhibiting calcium carbonate crystal growth in vitro via growth step frustration or interruption. However, very little is known with regard to the interactive capabilities of this sequence with Ca(II) and with calcium carbonates. Using multidisciplinary techniques, we determine that the AP7-1 polypeptide interacts with Ca(II) ions at the -DD- sequence clusters, yet retains its unfolded, conformationally labile structure in the presence of Ca(II) ions. Further, NMR experiments reveal that the extended structured sequence blocks, -GNGM-, -SVRTQG-, and -ISYL, exhibit motional, chemical exchange, and/or backbone geometry perturbations in response to Ca(II) interactions with AP7-1. Solid-state NMR magic angle spinning studies verify that during the course of in vitro calcium carbonate crystal growth, AP7-1 becomes bound to calcite fragments and cannot be entirely displaced from the mineral fragments using competitive Ca(II) washing. Finally, using a scrambled sequence version of the AP7-1 polypeptide, we observe that sequence scrambling does not adversely affect the crystal growth inhibitory activity of AP7-1, suggesting that the amino acid composition of AP7-1 may be more critical to growth step inhibition than the linear ordering of amino acids.",
author = "Kim, {Il Won} and Morse, {Daniel E.} and John Evans",
year = "2004",
month = "12",
day = "21",
doi = "10.1021/la0481400",
language = "English (US)",
volume = "20",
pages = "11664--11673",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "26",

}

TY - JOUR

T1 - Molecular characterization of the 30-AA N-terminal mineral interaction domain of the biomineralization protein AP7

AU - Kim, Il Won

AU - Morse, Daniel E.

AU - Evans, John

PY - 2004/12/21

Y1 - 2004/12/21

N2 - The AP7 protein is one of several mollusk shell proteins which are responsible for aragonite polymorph formation and stabilization within the nacre layer of the Pacific red abalone, H. rufescens. Previously, we demonstrated that the 30-AA N-terminal domain of AP7, denoted as AP7-1, exists as an unfolded sequence and possesses the capability of inhibiting calcium carbonate crystal growth in vitro via growth step frustration or interruption. However, very little is known with regard to the interactive capabilities of this sequence with Ca(II) and with calcium carbonates. Using multidisciplinary techniques, we determine that the AP7-1 polypeptide interacts with Ca(II) ions at the -DD- sequence clusters, yet retains its unfolded, conformationally labile structure in the presence of Ca(II) ions. Further, NMR experiments reveal that the extended structured sequence blocks, -GNGM-, -SVRTQG-, and -ISYL, exhibit motional, chemical exchange, and/or backbone geometry perturbations in response to Ca(II) interactions with AP7-1. Solid-state NMR magic angle spinning studies verify that during the course of in vitro calcium carbonate crystal growth, AP7-1 becomes bound to calcite fragments and cannot be entirely displaced from the mineral fragments using competitive Ca(II) washing. Finally, using a scrambled sequence version of the AP7-1 polypeptide, we observe that sequence scrambling does not adversely affect the crystal growth inhibitory activity of AP7-1, suggesting that the amino acid composition of AP7-1 may be more critical to growth step inhibition than the linear ordering of amino acids.

AB - The AP7 protein is one of several mollusk shell proteins which are responsible for aragonite polymorph formation and stabilization within the nacre layer of the Pacific red abalone, H. rufescens. Previously, we demonstrated that the 30-AA N-terminal domain of AP7, denoted as AP7-1, exists as an unfolded sequence and possesses the capability of inhibiting calcium carbonate crystal growth in vitro via growth step frustration or interruption. However, very little is known with regard to the interactive capabilities of this sequence with Ca(II) and with calcium carbonates. Using multidisciplinary techniques, we determine that the AP7-1 polypeptide interacts with Ca(II) ions at the -DD- sequence clusters, yet retains its unfolded, conformationally labile structure in the presence of Ca(II) ions. Further, NMR experiments reveal that the extended structured sequence blocks, -GNGM-, -SVRTQG-, and -ISYL, exhibit motional, chemical exchange, and/or backbone geometry perturbations in response to Ca(II) interactions with AP7-1. Solid-state NMR magic angle spinning studies verify that during the course of in vitro calcium carbonate crystal growth, AP7-1 becomes bound to calcite fragments and cannot be entirely displaced from the mineral fragments using competitive Ca(II) washing. Finally, using a scrambled sequence version of the AP7-1 polypeptide, we observe that sequence scrambling does not adversely affect the crystal growth inhibitory activity of AP7-1, suggesting that the amino acid composition of AP7-1 may be more critical to growth step inhibition than the linear ordering of amino acids.

UR - http://www.scopus.com/inward/record.url?scp=11144247938&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=11144247938&partnerID=8YFLogxK

U2 - 10.1021/la0481400

DO - 10.1021/la0481400

M3 - Article

C2 - 15595796

AN - SCOPUS:11144247938

VL - 20

SP - 11664

EP - 11673

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 26

ER -