Partial molar volumes of proteins: amino acid side-chain contributions derived from the partial molar volumes of some tripeptides over the temperature range 10–90°C

Häckel, Marko; Hinz, Hans‐Jürgen; Hedwig, Gavin R.

doi:10.1016/s0301-4622(99)00104-0

Cited by 104 publications

(85 citation statements)

References 65 publications

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“…A qualitatively similar behavior has been observed in densitometric studies of tripeptides. [11] The temperature dependence of the coefficient of thermal expansion of pure water is also shown in Figure 6 a (c). In particular it is noteworthy that a of pure water is negative below 4 8C.…”

Section: Discussionmentioning

confidence: 92%

“…Differences in hydration that accompany conformational changes in proteins are known to give rise to differences in their volumetric properties. [3][4][5][6][7][8][9][10][11] Hence, the study of pressure effects on proteins should, in principle, provide insight into these changes in hydration and the energetics and structural role of the solvent in determining the energy landscape of proteins. [12] Despite these prospects, using volumetric properties to understand the role of solvent in protein conformational transitions has been hindered due to a lack of fundamental and quantitative understanding of volume changes.…”

Section: Introductionmentioning

confidence: 99%

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Towards a Quantitative Understanding of Protein Hydration and Volumetric Properties

et al. 2008

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Herein, we probe by pressure perturbation calorimetry (PPC) the coefficient of thermal expansion, the volumetric and the hydration properties of variants of a hyperstable variant of staphylococcal nuclease (SNase), Delta+PHS. The temperature-dependent volumetric properties of the folded and unfolded states of the wild-type protein are calculated with previously published data. The present PPC results are used to interpret the volume diagram and expansivity at a molecular level. We conclude that the expansivity of the unfolded state is, to a first approximation, temperature independent, while that of the folded state decreases with increasing temperature. Our data suggest that at low temperature the defining contribution to DeltaV comes mainly from excluded volume differences and DeltaV for unfolding is negative. In contrast, at high temperatures, differential solvation due to the increased exposed surface area of the unfolded state and, in particular, its larger thermal volume linked to the increased conformational dynamics of the unfolded state ensemble takes over and DeltaV for unfolding eventually becomes positive.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Towards a Quantitative Understanding of Protein Hydration and Volumetric Properties

et al. 2008

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“…Apparent partial volumes of amino acids and proteins measured at concentrations below a few percent are nearly equal to the true partial volume at infinite dilution (8,(12)(13)(14)(15)(16). To a suitable approximation, this should also be true of apparent ␣ values obtained at low concentrations, and we refer to these as thermal coefficients of expansion of the partial volume and omit the apparent designation.…”

Section: Methodsmentioning

confidence: 99%

Determination of the Volumetric Properties of Proteins and Other Solutes Using Pressure Perturbation Calorimetry

Lin

Brandts

et al. 2002

Analytical Biochemistry

174

325

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“…In contrast, no correlation with pH i sensitivity was apparent (not shown). Neither pH i sensitivity nor pH o(50) values of the Ile-1079 substitution series correlated with side chain molecular weight, partial molar volume (27), van der Waals radius, solvent-accessible surface area (28), or charge separation index (29). The aa 1079 side chain may either block access to or modify the pK of a nearby titratable residue, as proposed for pH-sensitive K ϩ channels (30).…”

Section: Topographical Disposition Of the Rl1 Region Of The Ae2 Tmd-mentioning

confidence: 92%

Putative Re-entrant Loop 1 of AE2 Transmembrane Domain Has a Major Role in Acute Regulation of Anion Exchange by pH

Stewart

Kurschat

Vaughan‐Jones

et al. 2009

Journal of Biological Chemistry

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Normal pH sensitivity of the SLC4A2/AE2 anion exchanger requires transmembrane domain (TMD) amino acid (aa) residues not conserved in the homologous but relatively pH-insensitive SLC4A1/AE1 polypeptide. We tested the hypothesis that the nonconserved aa cluster 1075 DKPK 1078 within the first putative re-entrant loop (RL1) of AE2 TMD contributes to pH sensor function by studying anion exchange function of AE2 mutants in which these and other RL1 aa were systematically substituted with corresponding RL1 aa from AE1. 1078 restored pH i sensitivity to the chimera AE2 (1-920) /AE1 (613-929) without affecting its low sensitivity to pH o . The results show that acute regulation of AE2 by pH requires RL1 of the TMD. We propose that critical segments of RL1 constitute part of an AE2 pH sensor that, together with residues within the N-terminal half of the TMD, constrain the AE2 polypeptide in a conformation required for regulation of anion exchange by pH i .The mouse SLC4A2/AE2 anion exchanger regulates intracellular pH (pH i ), 3 chloride concentration, cell volume, and transepithelial ion transport in many tissues and is essential to postweaning life in mice (1). SLC4A2/AE2 and its paralogs SLC4A1/AE1 and SLC4A3/AE3 each mediate Na ϩ -independent electroneutral anion exchange (2). The AE polypeptides are expressed in distinct tissue and cell type-specific patterns and exhibit distinct modes of acute regulation. AE2 and AE3 but not AE1 are acutely regulated by pH i (3). AE2 is also acutely regulated by extracellular pH (pH o ), NH 4 ϩ , hypertonicity, and (in a calmodulin-independent manner) calmidazolium (4, 5). Although the structural basis for these regulatory differences is not completely understood, recent structure-function analysis studies have identified isoform-specific residues in both N-terminal cytoplasmic and C-terminal transmembrane domains of AE2 that are required for acute regulation (4, 6).The 400 -700-aa N-terminal cytoplasmic domains of the SLC4 AE gene products are divergent in sequence, with only 35% aa identity between AE2 and AE1. The better conserved ϳ500-aa transmembrane domains (TMDs) of AE1, AE2, and AE3 share ϳ65% sequence identity. Even in the absence of their N-terminal cytoplasmic domains, AE TMDs expressed in erythrocytes, Xenopus oocytes, or mammalian cells can mediate electroneutral anion exchange (7-9). However, removal of all or part of the AE2 N-terminal cytoplasmic domain alters its acute regulation by pH, NH 4 ϩ , hypertonicity, and calmidazolium (5). Mutation of individual aa residues of the N-terminal cytoplasmic domain partially or completely recapitulates these regulatory changes. Moreover, many of these residues are predicted to reside on the surface of the N-terminal cytoplasmic domain (6). Removal of the N-terminal cytoplasmic domain from the AE2 TMD abolishes regulation by pH i (10) and significantly acid-shifts the pH o versus activity profile compared with wild-type AE2 (9). These findings suggest the presence of a pH sensor motif within the AE2 TMD that cooperates with se...

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Partial molar volumes of proteins: amino acid side-chain contributions derived from the partial molar volumes of some tripeptides over the temperature range 10–90°C

Cited by 104 publications

References 65 publications

Towards a Quantitative Understanding of Protein Hydration and Volumetric Properties

Towards a Quantitative Understanding of Protein Hydration and Volumetric Properties

Determination of the Volumetric Properties of Proteins and Other Solutes Using Pressure Perturbation Calorimetry

Putative Re-entrant Loop 1 of AE2 Transmembrane Domain Has a Major Role in Acute Regulation of Anion Exchange by pH

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