Linked Life Data

18067326

Source:http://linkedlifedata.com/resource/pubmed/id/18067326

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-1-3
pubmed:abstractText
This work describes differential effects of solvent in complexes of the aminoglycoside phosphotransferase(3')-IIIa (APH) with different aminoglycosides and the detection of change in solvent structure at specific sites away from substrates. Binding of kanamycins to APH occurs with a larger negative DeltaH in H2O relative to D2O (DeltaDeltaH(H2O-D2O) < 0), while the reverse is true for neomycins. Unusually large negative DeltaCp values were observed for binding of aminoglycosides to APH. DeltaCp for the APH-neomycin complex was -1.6 kcal x mol(-1) x deg(-1). A break at 30 degrees C was observed in the APH-kanamycin complex yielding DeltaCp values of -0.7 kcal x mol(-1) x deg(-1) and -3.8 kcal x mol(-1) x deg(-1) below and above 30 degrees C, respectively. Neither the change in accessible surface area (DeltaASA) nor contributions from heats of ionization were sufficient to explain the large negative DeltaCp values. Most significantly, 15N-1H HSQC experiments showed that temperature-dependent shifts of the backbone amide protons of Leu 88, Ser 91, Cys 98, and Leu143 revealed a break at 30 degrees C only in the APH-kanamycin complex in spectra collected between 21 degrees C and 38 degrees C. These amino acids represent solvent reorganization sites that experience a change in solvent structure in their immediate environment as structurally different ligands bind to the enzyme. These residues were away from the substrate binding site and distributed in three hydrophobic patches in APH. Overall, our results show that a large number of factors affect DeltaCp and binding of structurally different ligand groups cause different solvent structure in the active site as well as differentially affecting specific sites away from the ligand binding site.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
8
pubmed:volume
47
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
40-9
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Detection of specific solvent rearrangement regions of an enzyme: NMR and ITC studies with aminoglycoside phosphotransferase(3')-IIIa.
pubmed:affiliation
Graduate School of Genome Science and Technology, University of Tennessee and Oak Ridge National Laboratories, Knoxville, Tennessee 37996-0840, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't