Linked Life Data

8399142

Source:http://linkedlifedata.com/resource/pubmed/id/8399142

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
38
pubmed:dateCreated
1993-11-2
pubmed:abstractText
To clarify the effects of specific inter- and intrasubunit hydrogen bonds on the R-T transition in human hemoglobin (Hb A), the recombination reaction of carbon monoxide with artificial mutant Hbs was measured and analyzed. One of the hydrogen bonds we focused on is formed between Tyr-42 alpha and Asp-99 beta in the alpha 1-beta 2 interface of Hb A, which is one of the hydrogen bonds characteristic of the T state. Hb His-42 alpha, in which Tyr-42 alpha is replaced by His to perturb this hydrogen bond, showed that the ligand-free R to T transition rate was decreased by 20-fold compared with that for Hb A. This mutation caused the destabilization of the transition state in the R to T quaternary structure change by about 7 kJ mol-1, indicating that the hydrogen bond between Tyr-42 alpha and Asp-99 beta plays a definite role in the R-T transition as well as in stabilization of the equilibrium T state. Hb Phe-145 beta, in which Tyr-145 beta is replaced by Phe and the intrasubunit hydrogen bond between Tyr-145 beta and Val-98 beta is lacking, also showed a slow R-T transition rate as observed in Hb His-42 alpha. The published crystallographic data suggest that this intrasubunit hydrogen bond stabilizes the transition state by reducing the freedom of motion of the C-terminus of the beta subunit and, thereby, facilitates the R-T transition.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10165-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Effects of intra- and intersubunit hydrogen bonds on the R-T transition in human hemoglobin as studied with alpha 42(C7) and beta 145(HC2) mutations.
pubmed:affiliation
Division of Molecular Engineering, Graduate School of Engineering, Kyoto University, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't