Premium
Surface‐enhanced Raman difference between bombesin and its modified analogues on the colloidal and electrochemically roughen silver surfaces
Author(s) -
Podstawka Edyta,
Ozaki Yukihiro
Publication year - 2008
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.21017
Subject(s) - chemistry , adsorption , bombesin , raman spectroscopy , molecule , crystallography , silver nanoparticle , raman scattering , moiety , stereochemistry , nanoparticle , organic chemistry , nanotechnology , biochemistry , physics , receptor , materials science , neuropeptide , optics
Abstract In this article, surface‐enhanced Raman scattering (SERS) spectra of bombesin ( BN ) and its six modified analogues ( [D‐Phe 12 ]BN , [Tyr 4 ]BN , [Tyr 4 ,D‐Phe 12 ]BN , [D‐Phe 12 ,Leu 14 ]BN , [Leu 13 ‐®‐Leu 14 ]BN , and [Lys 3 ]BN ) on a colloidal silver surface are reported and compared with SERS spectra of these species immobilized onto an ellectrochemically roughen silver electrode. Changes in enhancement and wavenumber of proper bands upon adsorption on different silver surfaces are consistent with BN and its analogues adsorption primarily through Trp 8 . Slightly different adsorption states of these molecules are observed depending upon natural amino acids substitution. For example, the indole ring in all the peptides interacts with silver nanoparticles in a edge‐on orientation. It is additionally coordinated to the silver through the N 1 H bond for all the peptides, except [Phe 12 ]BN . This is in contrary to the results obtained for the silver roughen electrode that show direct but not strong N 1 H/Ag interaction for all peptides except [D‐Phe 12 ,Leu 14 ]BN and [Leu 13 ‐®‐Leu 14 ]BN . For BN only CO is not involved in the chemical coordination with the colloidal surface. [Lys 3 ]BN and BN also adsorb with the CN bond of NH 2 group normal and horizontal, respectively, to the colloidal surface, whereas CNH 2 in other peptides is tilted to this surface. Also, the Trp 8 CH 2 moiety of only [Tyr 4 ]BN , [Lys 3 ]BN , and [Tyr 4 ,D‐Phe 12 ]BN coordinates to Ag, whereas the Phe 12 ring of [Phe 12 ]BN , [Tyr 4 ,D‐Phe 12 ]BN , and [D‐Phe 12 ,Leu 14 ]BN assists in the peptides binding only on the colloidal silver. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 807–819, 2008. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com