Temperature and pH dependence of the tetramer-dimer equilibrium of carbomonoxyhemoglobin A0

Ide, G; Barksdale, Alfred D.; Rosenberg, Andreas

doi:10.1021/ja00422a060

Cited by 13 publications

(3 citation statements)

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“…1). The dynamic properties of RNase S should therefore be concentration dependent (27,32). In the present work, we provide quantitative support for this hypothesis by carrying out concentration-dependent hydrogen exchange studies of RNase A and RNase S by using one-dimensional (1D) and 2D NMR.…”

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confidence: 52%

Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments

Chakshusmathi

Ratnaparkhi

Madhu

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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Ordered protein complexes are often formed from partially ordered fragments that are difficult to structurally characterize by conventional NMR and crystallographic techniques. We show that concentration-dependent hydrogen exchange studies of a fragment complex can provide structural information about the solution structures of the isolated fragments. This general methodology can be applied to any bimolecular or multimeric system. The experimental system used here consists of Ribonuclease S, a complex of two fragments of Ribonuclease A. Ribonuclease S and Ribonuclease A have identical three-dimensional structures but exhibit significant differences in their dynamics and stability. We show that the apparent large dynamic differences between Ribonuclease A and Ribonuclease S are caused by small amounts of free fragments in equilibrium with the folded complex, and that amide exchange rates in Ribonuclease S can be used to determine corresponding rates in the isolated fragments. The studies suggest that folded RNase A and the RNase S complex exhibit very similar dynamic behavior. Thus cleavage of a protein chain at a single site need not be accompanied by a large increase in f lexibility of the complex relative to that of the uncleaved protein.

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mentioning

confidence: 52%

Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments

Chakshusmathi

Ratnaparkhi

Madhu

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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“…The method is useful for studying the conformation and conformational fluctuations of a protein since the rate of amide proton exchange is greatly reduced in native proteins (by as much as 108) when the amide proton is hydrogen bonded or when it is otherwise protected from solvent. Recently, amide proton exchange has been used to (a) study conformational fluctuations in lysozyme (Knox & Rosenberg, 1980) and ribonuclease S (Rosa & Richards, 1979, (b) measure the dissociation constants of hemoglobin (Ide et al, 1976) and of ribonuclease S (Schreier & Baldwin, 1976,1977, (c) study ligand-induced conformational changes in hemoglobin (Englander et al, 1980), and (d) probe the structures of intermediates in the folding of ribonuclease A (Schmid & Baldwin, 1979; Kim & Baldwin, 1980). The NMR1 assignment of the slowly exchanging amide protons in BPTI by Dubs et al (1979) 0006-2960/82/0421-0001$01.25/0 shift of 1.3 pH units in the pHmin of POLL between 0 and 2 M NaCl.…”

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confidence: 99%

Influence of charge on the rate of amide proton exchange

Kim¹,

Baldwin²

1982

Biochemistry

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“…The dimer‐tetramer association constant obtained by gel filtration is 1.0±0.2×10 4 M −1 at pH 5.0 and 10°C. No significant changes in the values of K 2,4 have been reported in the range of temperatures used and no correction for the K 2,4 values was applied [13, 14]. The value obtained for K 2,4 was used as a fixed parameter for the data fit of Fig.…”

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confidence: 99%

Immobilized apo‐myoglobin, a new stable reagent for measuring rates of heme dissociation from hemoglobin

1998

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Apo-myoglobin covalently linked on CNBr-activated Sepharose 4B is proposed as a new heme acceptor for investigating the heme transfer reaction from hemoproteins. Immobilized apo-myoglobin has the desirable properties of an ideal heme acceptor in that it is characterized by a high affinity for ferric heme, a high stability towards denaturation even at physiological temperatures and can be lyophilized for long-term storage. The study of heme release from myoglobin at pH 5.0 and 37³C indicates that heme affinity is increased at least 10-fold relative to the soluble protein. Experiments with human hemoglobin allowed the estimation of the heme release rates from both K K and L L chains and brought out the greater temperature sensitivity of the K K chain heme-globin linkage. z 1998 Federation of European Biochemical Societies.

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Temperature and pH dependence of the tetramer-dimer equilibrium of carbomonoxyhemoglobin A0

Cited by 13 publications

References 0 publications

Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments

Native-state hydrogen-exchange studies of a fragment complex can provide structural information about the isolated fragments

Influence of charge on the rate of amide proton exchange

Immobilized apo‐myoglobin, a new stable reagent for measuring rates of heme dissociation from hemoglobin

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