Linked Life Data

16833362

Source:http://linkedlifedata.com/resource/pubmed/id/16833362

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2006-7-12
pubmed:abstractText
Resonance Raman spectra of porphyrins are computed with DFT/CIS methodology to monitor out-of-plane distortions. A framework is established for assessing protein-induced distortion of porphyrin bound to a ferrochealatase antibody. Tests on undistorted porphyrins give good agreement with the experimental intensity pattern of in-plane modes for free-base porphine (FBP) and mesorporphyrin IX free base (MP). The computed spectrum of N-methylmesoporphyrin (NMP), in which the methyl-substituted pyrrole ring is tilted 32 degrees from the mean porpyrin plane, also gives reasonable agreement with experiment and reveals activation of out-of-plane (oop) vibrational modes. To model oop distortions systematically, an artificial molecule, FBP-X8, was constructed, in which the H atoms attached to the FBP pyrrole Cb atoms are replaced by heavy substituents, as in physiological porphyrins. Oop mode enhancements are computed for FBP-X8 by displacing it along the canonical distortion coordinates: doming, saddling, ruffling and waving. When FBP-X8 is constrained to the NMP porphyrin geometry, normal coordinate decomposition reveals significant contributions also from modes higher in frequency than the canonical modes, and they contribute importantly to the computed RR intensities. NMP-constrained FBP-X8 gives a reasonable facsimile of the NMP RR spectrum, but better results are obtained with a full computation of MP, constrained in the same way; thus the physiological substituents have significant influence on the RR spectra, over and above their effective masses. Attention focuses on a mode analogous to gamma 15 in 4-fold symmetric porphyrins, which is a kind of saddling mode. This mode is selectively enhanced in NMP-constrained MP; a corresponding RR band is induced upon binding MP to a ferrochelatase antibody.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1089-5639
pubmed:author
pubmed:issnType
Print
pubmed:day
27
pubmed:volume
109
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
421-30
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Porphyrin distortion from resonance Raman intensities of out-of-plane modes: Computation and modeling of N-methylmesoporphyrin, a ferrochelatase transition state analog.
pubmed:affiliation
Department of Chemistry, Princeton University, Princeton New Jersey 08544, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural