Electrostatic Effects in Proteins

Matthew, James B.

doi:10.1146/annurev.bb.14.060185.002131

Cited by 313 publications

(134 citation statements)

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“…Specific interaction aside, altering the salt concentration will result in an alteration in the ionic strength of the buffer, unless controlled for. An alteration in the ionic strength could affect interactions between amino acids residues in a protein by electrostatic screening [21] [22] leading to changes in the structural properties of the protein [23]. Therefore, an attempt was made to determine the role of Na + ions on the structure of the cGMP-binding GAFa domain of PDE5.…”

Section: Resultsmentioning

confidence: 99%

Buffer NaCl concentration regulates Renilla luciferase activity and ligand-induced conformational changes in the BRET-based PDE5 sensor

Biswas

Visweswariah

2017

Matters

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Section: Resultsmentioning

confidence: 99%

Buffer NaCl concentration regulates Renilla luciferase activity and ligand-induced conformational changes in the BRET-based PDE5 sensor

Biswas

Visweswariah

2017

Matters

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“…With a pK value of 10.1 in solution, tyrosine is a protonizable amino acid residue in alkaline regions (35). When the medium pH was changed to 12, the structure of MSP was shown to become totally unfolded (13).…”

Section: Resultsmentioning

confidence: 99%

Structural and Functional Differentiation of Three Groups of Tyrosine Residues by Acetylation of N-Acetylimidazole in Manganese Stabilizing Protein

et al. 2004

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To study its contribution to the assembly of the green plant manganese stabilizing protein (MSP) into photosystem II (PSII), tyrosine residues were specifically acetylated using N-acetylimidazole (NAI). In soluble MSP, three groups of Tyr residues could be differentiated by NAI acetylation: approximately 5 (actually ∼5.2) Tyr residues could be easily acetylated (superficial), 1-2 Tyr residues could be acetylated when the NAI concentration was sufficiently high (superficially buried), and 1-2 Tyr residues could only be acetylated in the presence of the denaturant, urea (deeply buried). Acetylation of the 5.2 Tyr residues did not affect the reconstitution or oxygen-evolving activities of the MSP, and far-UV circular dichroism (CD) analysis showed that the altered MSP retained most of its native secondary structure. These results suggested that the 5.2 Tyr residues are not absolutely essential to the function of MSP. However, further modification of the 1-2 superficially buried Tyr residues (for a total acetylation of ∼6.4 Tyr residues) completely abrogated the MSP rebinding and oxygen evolution activities. Finally, at least one tyrosine residue was inaccessible to NAI until MSP was completely unfolded by 8 M urea. Deacetylation of MSP with 6.4 or 8 acetylated Tyr residues with hydroxylamine restored most of the rebinding and oxygen-evolving activities. A prominent red shift in fluorescence spectra of MSP (excited at 280 or 295 nm) was observed after modification of 6.4 Tyr residues, and a further shift could be found after all 8 Tyr residues were modified, indicating a great loss of native secondary structure. Far-UV CD revealed that MSP was mostly unfolded when 6.4 Tyr residues were modified and completely unfolded when all 8 Tyr residues were modified. Fluorescence and far-UV CD studies revealed that loss of MSP rebinding to PSII membranes following NAI modification correlated well with conformational changes in MSP. Together, these results indicate that different tyrosine residues have different contributions to the binding and assembly of MSP into PSII.In green plants, photosystem II (PSII) 1 catalyzes the lightdriven reduction of plastoquinone and the oxidation of water to molecular oxygen (1). All major components of PSII required for its activity, including chlorophyll a (P680), tyrosine (Y Z ), pheophytin (Pheo), and the primary (Q A ) and secondary (Q B ) quinone acceptors are located within a heterodimeric matrix consisting of polypeptides D1 and D2. Although the essential pathway for photosynthetic water oxidation into molecular oxygen and protons has been established, a detailed comprehensive picture of water oxidation has not been elucidated to date. In particular, the manganese cluster of the water-oxidizing complex (WOC) is not well understood. Site-directed mutagenesis experiments have revealed that several amino acid residues of D1 and D2 are functionally and/or structurally relevant for establishing a competent WOC. However, other extrinsic polypeptides cannot be excluded as being essen...

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“…Indeed, the rate-limiting step in the formation of the complex appears to be the electrostatic interaction between the C-terminal tail of hirudin and the fibrinogenrecognition exosite (Stone & Hofsteenge, 1986). This phenomenon known as "electrostatic steering" has been postulated to be important in the association of other molecules (Matthew, 1985;Klapper et al, 1986;Sharp et al, 1987;Northrup et al, 1988;Tulinsky et al, 1988).…”

Section: Discussionmentioning

confidence: 99%

“…The pK values of the titratable groups were calculated (Karshikov et al, 1989), and then the charges on these groups were determined from the pK values. The intrinsic pK values used in these calculations were taken from Matthew (1985).…”

Section: Methods Of Calculationsmentioning

confidence: 99%

Electrostatic interactions in the association of proteins: An analysis of the thrombin–hirudin complex

et al. 1992

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The role of electrostatic interactions in stabilization of the thrombin-hirudin complex has been investigated by means of two macroscopic approaches: the modified Tanford-Kirkwood model and the finite-difference method for numerical solution of the Poisson-Boltzmann equations. The electrostatic potentials around the thrombin and hirudin molecules were asymmetric and complementary, and it is suggested that these fields influence the initial orientation in the process of the complex formation. The change of the electrostatic binding energy due to mutation of acidic residues in hirudin has been calculated and compared with experimentally determined changes in binding energy. In general, the change in electrostatic binding energy for a particular mutation calculated by the modified Tanford-Kirkwood approach agreed well with the experimentally observed change. The finitedifference approach tended to overestimate changes in binding energy when the mutated residues were involved in short-range electrostatic interactions. Decreases in binding energy caused by mutations of amino acids that do not make any direct ionic interactions (e.g., Glu 61 and Glu 62 of hirudin) can be explained in terms of the interaction of these charges with the positive electrostatic potential of thrombin. Differences between the calculated and observed changes in binding energy are discussed in terms of the crystal structure of the thrombin-hirudin complex.Keywords: electrostatic interactions; hirudin; protein-protein interactions; thrombin Thrombin is a serine protease that plays a central role in blood coagulation. It cleaves fibrinogen to yield fibrin monomers that form the basis of the blood clot. In addition, thrombin activates a number of other proteins involved in coagulation. Thrombin can be distinguished from other serine proteases, such as trypsin, in that it achieves its specificity by using binding sites, called exosites, that are distant from the catalytic center (Fenton, 1988). The crystal structures of thrombin (Bode et al., 1989(Bode et al., , 1992 and its complexes with the polypeptide inhibitor hirudin (Kinemage 1; Griitter et al., 1990;Rydel et al., 1990Rydel et al., , 1991 cleft of thrombin, the C-terminal region binds to a positively charged surface groove called the fibrinogen-recognition exosite. The C-terminal region of recombinant hirudin (rhir) between residues 55 and 65 contains five negatively charged residues, and results from studies using site-directed mutagenesis indicate that each of these negatively charged residues (Asp 55: Glu 57: Glu 58: Glu 61', and Glu 62') contributes to the stabilization of the complex (Braun et al., 1988a;Betz et al., 1991). In addition, the effect of ionic strength on the interaction between thrombin and hirudin suggests that electrostatic interactions with the C-terminal region of hirudin are important for the rate of complex formation and the stability of the complex (Stone et al., 1989). However, although protein engineering studies indicate that each of the negatively char...

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Electrostatic Effects in Proteins

Cited by 313 publications

References 0 publications

Buffer NaCl concentration regulates Renilla luciferase activity and ligand-induced conformational changes in the BRET-based PDE5 sensor

Buffer NaCl concentration regulates Renilla luciferase activity and ligand-induced conformational changes in the BRET-based PDE5 sensor

Structural and Functional Differentiation of Three Groups of Tyrosine Residues by Acetylation of N-Acetylimidazole in Manganese Stabilizing Protein

Electrostatic interactions in the association of proteins: An analysis of the thrombin–hirudin complex

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