Linked Life Data

18928314

Source:http://linkedlifedata.com/resource/pubmed/id/18928314

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2009-2-20
pubmed:abstractText
Second-harmonic generation (SHG) is highly sensitive to the net, average orientation of SH-active molecules on surfaces and has recently emerged as a technique for detecting biomolecules and their conformational changes. As most biomolecules are not intrinsically SH-active, they must be labeled with probes to render them detectable. To date, exogenous probes have been used to do this, but second-harmonic-active unnatural amino acids offer important advantages for the long-range goal of precisely and directly determining structural changes in real time and may be used for both buried and surface sites. Results of the first known SH-active unnatural amino acid, Aladan, are presented here. Aladan is found to be SH-active by detecting it at an interface, both alone and incorporated into the B1 domain of protein G (GB1), a globular immunoglobulin-binding protein, at both buried and exposed sites. The tilt angle of Aladan alone adsorbed on a mica surface is determined by polarization experiments, and its nonlinear polarizability alpha((2)) is found to be ca. 10(-30) esu. Aladan GB1 mutants are detectable by SHG, either when coupled covalently to a derivatized glass surface or bound to IgG immobilized via protein A. Addition of an Fc domain to this GB1 complex causes a small but defined change in the SH signal when Aladan is incorporated at site Ala(24), but not at Leu(7), consistent with a local conformational change of GB1. This structural change is not apparent in either X-ray crystallography or fluorescence studies, demonstrating that SHG can detect subtle orientational changes, including protein-protein interactions in which no significant rearrangements occur.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1520-6106
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
112
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15103-7
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
A second-harmonic-active unnatural amino acid as a structural probe of biomolecules on surfaces.
pubmed:affiliation
Biodesy, LLC, Burlingame, California 94010, USA. salafsky@biodesy.com
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.