Molecular characterization of a prokaryotic polypeptide sequence that catalyzes Au crystal formation

John L. Kulp, Mehmet Sarikaya, John Evans

Research output: Contribution to journalArticle

Abstract

The gold crystal-forming E. coli polypeptide sequence, MHGKTQATSGTIQS, is one of several polypeptide sequences that interacts with gold interfaces and catalyzes the formation of Au crystals in solution, with nucleated Au crystals preferentially featuring the (111) interface. To date, there have been no experimental studies which explore the structure of E. coli-expressed gold binding proteins or the binding of Au(III) ions by these polypeptides. In this present report, multidisciplinary approaches were applied to the 42-AA gold binding protein-1 (GBP-1/42) and to a model polypeptide representing the 14-AA integral repeat of this protein (GBP-1/14). CD and NMR spectroscopy indicate that neither the integral repeat nor the GBP-1 protein adopt folded structures in the apo form or in the presence of Au(III) ions; the integral repeat adopts a random coil-extended structure conformation [i.e., (MHGKTQA)random coil-(TSGTIQS)extended] and the GBP-1 protein appears to be similarly structured. These features are inconsistent with a templating structure. Mass spectrometry experiments indicate that the integral repeat binds up to two Au(III) ions per polypeptide molecule, and 1H NMR ROESY experiments pinpoint the interaction of Au(III) within two sites: the -QAT- region of the integral repeat MHGKTQATSGTIQS sequence, and, at the negatively charged C-terminus of this sequence. Collectively, our findings support the hypothesis that GBP-1 does not catalyze Au crystal formation via a templating mechanism; rather, the open, unfolded structure of this protein, combined with the presence of accessible proton donor/acceptor amino acids (Ser, Thr, Lys, Gln, His) most likely play a role in Au crystal formation in solution and may also explain the interactive nature of this polypeptide with Au interfaces.

Original languageEnglish (US)
Pages (from-to)2325-2332
Number of pages8
JournalJournal of Materials Chemistry
Volume14
Issue number14
DOIs
StatePublished - Jul 21 2004

Fingerprint

Polypeptides
polypeptides
proteins
Gold
Peptides
Crystals
gold
crystals
Proteins
Ions
Escherichia coli
Carrier Proteins
coils
nuclear magnetic resonance
ions
Nuclear magnetic resonance spectroscopy
Mass spectrometry
amino acids
Conformations
Protons

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Chemistry
  • Materials Science(all)

Cite this

Molecular characterization of a prokaryotic polypeptide sequence that catalyzes Au crystal formation. / Kulp, John L.; Sarikaya, Mehmet; Evans, John.

In: Journal of Materials Chemistry, Vol. 14, No. 14, 21.07.2004, p. 2325-2332.

Research output: Contribution to journalArticle

@article{a38b1e94ce844f64acd3f553f1e05b2b,
title = "Molecular characterization of a prokaryotic polypeptide sequence that catalyzes Au crystal formation",
abstract = "The gold crystal-forming E. coli polypeptide sequence, MHGKTQATSGTIQS, is one of several polypeptide sequences that interacts with gold interfaces and catalyzes the formation of Au crystals in solution, with nucleated Au crystals preferentially featuring the (111) interface. To date, there have been no experimental studies which explore the structure of E. coli-expressed gold binding proteins or the binding of Au(III) ions by these polypeptides. In this present report, multidisciplinary approaches were applied to the 42-AA gold binding protein-1 (GBP-1/42) and to a model polypeptide representing the 14-AA integral repeat of this protein (GBP-1/14). CD and NMR spectroscopy indicate that neither the integral repeat nor the GBP-1 protein adopt folded structures in the apo form or in the presence of Au(III) ions; the integral repeat adopts a random coil-extended structure conformation [i.e., (MHGKTQA)random coil-(TSGTIQS)extended] and the GBP-1 protein appears to be similarly structured. These features are inconsistent with a templating structure. Mass spectrometry experiments indicate that the integral repeat binds up to two Au(III) ions per polypeptide molecule, and 1H NMR ROESY experiments pinpoint the interaction of Au(III) within two sites: the -QAT- region of the integral repeat MHGKTQATSGTIQS sequence, and, at the negatively charged C-terminus of this sequence. Collectively, our findings support the hypothesis that GBP-1 does not catalyze Au crystal formation via a templating mechanism; rather, the open, unfolded structure of this protein, combined with the presence of accessible proton donor/acceptor amino acids (Ser, Thr, Lys, Gln, His) most likely play a role in Au crystal formation in solution and may also explain the interactive nature of this polypeptide with Au interfaces.",
author = "Kulp, {John L.} and Mehmet Sarikaya and John Evans",
year = "2004",
month = "7",
day = "21",
doi = "10.1039/b401260g",
language = "English (US)",
volume = "14",
pages = "2325--2332",
journal = "Journal of Materials Chemistry",
issn = "0959-9428",
publisher = "Royal Society of Chemistry",
number = "14",

}

TY - JOUR

T1 - Molecular characterization of a prokaryotic polypeptide sequence that catalyzes Au crystal formation

AU - Kulp, John L.

AU - Sarikaya, Mehmet

AU - Evans, John

PY - 2004/7/21

Y1 - 2004/7/21

N2 - The gold crystal-forming E. coli polypeptide sequence, MHGKTQATSGTIQS, is one of several polypeptide sequences that interacts with gold interfaces and catalyzes the formation of Au crystals in solution, with nucleated Au crystals preferentially featuring the (111) interface. To date, there have been no experimental studies which explore the structure of E. coli-expressed gold binding proteins or the binding of Au(III) ions by these polypeptides. In this present report, multidisciplinary approaches were applied to the 42-AA gold binding protein-1 (GBP-1/42) and to a model polypeptide representing the 14-AA integral repeat of this protein (GBP-1/14). CD and NMR spectroscopy indicate that neither the integral repeat nor the GBP-1 protein adopt folded structures in the apo form or in the presence of Au(III) ions; the integral repeat adopts a random coil-extended structure conformation [i.e., (MHGKTQA)random coil-(TSGTIQS)extended] and the GBP-1 protein appears to be similarly structured. These features are inconsistent with a templating structure. Mass spectrometry experiments indicate that the integral repeat binds up to two Au(III) ions per polypeptide molecule, and 1H NMR ROESY experiments pinpoint the interaction of Au(III) within two sites: the -QAT- region of the integral repeat MHGKTQATSGTIQS sequence, and, at the negatively charged C-terminus of this sequence. Collectively, our findings support the hypothesis that GBP-1 does not catalyze Au crystal formation via a templating mechanism; rather, the open, unfolded structure of this protein, combined with the presence of accessible proton donor/acceptor amino acids (Ser, Thr, Lys, Gln, His) most likely play a role in Au crystal formation in solution and may also explain the interactive nature of this polypeptide with Au interfaces.

AB - The gold crystal-forming E. coli polypeptide sequence, MHGKTQATSGTIQS, is one of several polypeptide sequences that interacts with gold interfaces and catalyzes the formation of Au crystals in solution, with nucleated Au crystals preferentially featuring the (111) interface. To date, there have been no experimental studies which explore the structure of E. coli-expressed gold binding proteins or the binding of Au(III) ions by these polypeptides. In this present report, multidisciplinary approaches were applied to the 42-AA gold binding protein-1 (GBP-1/42) and to a model polypeptide representing the 14-AA integral repeat of this protein (GBP-1/14). CD and NMR spectroscopy indicate that neither the integral repeat nor the GBP-1 protein adopt folded structures in the apo form or in the presence of Au(III) ions; the integral repeat adopts a random coil-extended structure conformation [i.e., (MHGKTQA)random coil-(TSGTIQS)extended] and the GBP-1 protein appears to be similarly structured. These features are inconsistent with a templating structure. Mass spectrometry experiments indicate that the integral repeat binds up to two Au(III) ions per polypeptide molecule, and 1H NMR ROESY experiments pinpoint the interaction of Au(III) within two sites: the -QAT- region of the integral repeat MHGKTQATSGTIQS sequence, and, at the negatively charged C-terminus of this sequence. Collectively, our findings support the hypothesis that GBP-1 does not catalyze Au crystal formation via a templating mechanism; rather, the open, unfolded structure of this protein, combined with the presence of accessible proton donor/acceptor amino acids (Ser, Thr, Lys, Gln, His) most likely play a role in Au crystal formation in solution and may also explain the interactive nature of this polypeptide with Au interfaces.

UR - http://www.scopus.com/inward/record.url?scp=4043107684&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=4043107684&partnerID=8YFLogxK

U2 - 10.1039/b401260g

DO - 10.1039/b401260g

M3 - Article

VL - 14

SP - 2325

EP - 2332

JO - Journal of Materials Chemistry

JF - Journal of Materials Chemistry

SN - 0959-9428

IS - 14

ER -