Linked Life Data

9047335

Source:http://linkedlifedata.com/resource/pubmed/id/9047335

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1997-3-25
pubmed:abstractText
A synthetic gene for chicken ovomucoid first domain (OMCHI1) has been overexpressed in Escherichia coli. The resulting recombinant protein, rOMCHI1, is expressed and correctly folded without the use of fusion proteins or export secretion signal peptides incorporated into the gene. The thermostability of rOMCHI1 has been compared to that of the naturally occurring glycosylated OMCHI1 (gOMCHI1). The results of differential scanning calorimetry (DSC) studies show that the heat capacity change for unfolding, deltaCp, for both rOMCHI1 and gOMCHI1 is approximately 600 cal/(mol x K). At any given pH, however, the presence of N-linked carbohydrate increases the Tm for thermal unfolding of gOMCHI1 over rOMCHI1 by 2-4 degrees C, without changing the enthalpy of unfolding, delta H(degree)m. This suggests that the increased thermal stability of gOMCHI1 is entropic. Comparison of the unfolding thermodynamics of rOMCHI1 with those of turkey ovomucoid third domain (OMTKY3), which is 36% identical to rOMCHI1, reveals similar deltaCp values for both proteins, about 600 cal/(mol x K), but a reduction in delta H(degree)m of about 5 kcal/mol for rOMCHI1 at all temperatures. Decreases in delta H(degree)m for rOMCHI1 versus OMTKY3 may be explained by an overall less ordered native state in rOMCHI1. In the absence of a native structure for OMCHI1, the change in accessible surface area upon unfolding, deltaASA, was calculated using unfolding parameters and structural energetic relationships [Murphy & Freire (1992) Adv. Protein Chem. 43, 313-361; Murphy et al. (1993), Proteins: Struct., Funct., Genet. 15, 113-120]. These calculations suggest that the larger protein rOMCHI1 (Mr 7500) exposes less surface area than OMTKY3 (Mr 6100) upon thermal denaturation. Overall, structural energetic relationships may provide a useful framework for interpretation and comparison of thermodynamic data for structurally homologous proteins.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2323-31
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Thermodynamics of unfolding for Kazal-type serine protease inhibitors: entropic stabilization of ovomucoid first domain by glycosylation.
pubmed:affiliation
Department of Biochemistry, The University of Iowa, Iowa City 52242, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.