Fabian Muñoz - Academia.edu (original) (raw)
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Papers by Fabian Muñoz
International Journal of Biological Macromolecules, 1985
Absorption difference spectra of phosphorylase b when AMP binds to its high affinity site have be... more Absorption difference spectra of phosphorylase b when AMP binds to its high affinity site have been studied at 25°C and pH 6.9; the absorbance changes show linearity as a function of the amount of phophorylase b-AMP complex present in solution. The negative regions of these spectra have been interpreted by assigning the hypochromic effect in the absorption band of AMP to stacking of the adenine ring with an aromatic ring from some tyrosine and/or tryptophan residues. On the other hand, the positive region of the difference spectrum induced by binding of AMP to its high affinity site can be simulated assuming that six tyrosines and one or two tryptophans per monomer are embedded in a highly hydrophobic environment.
Biopolymers, 1998
In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and n... more In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and neutral, has been carried out. The preferred conformations were determined by means of ab initio and semiempirical quantum, together with empirical force field calculations. The AMBER* force field and the 6-31 / G** and 6-31G** ab initio levels give rise to a coincident minimum energy structure, which, on the other hand, differs from that determined by AM1, 3-21 / G, and 3-21G. The solvent effect on the different charged and neutral conformations have been considered through the AMSOL semiempirical method. A quantification regarding the structural similarities between the different dipeptide conformations and the ampicillin has been performed. The results show that the best overlay is attained by the minimum structure energy obtained by using the 6-31
International Journal of Biological Macromolecules, 1985
Equilibrium dialysis measurements have been performed at several temperatures, ranging from 5 to ... more Equilibrium dialysis measurements have been performed at several temperatures, ranging from 5 to 30°C, to calculate the binding constants of AMP to phosphorylase b (EC 2.4.1.1). AH=-lOkcal/mol and AS = -16.4 e.u. have been obtained for the binding process. Measurements of enzymatic activity have been performed in the same temperature range. An activation energy of16 kcal has been calculated for the enzymecatalysed reaction. Absorption difference spectra induced by AMP in phosphorylase b when AMP is bound to its high affinity site have also been carried out at these temperatures. The equilibrium constant for the binding of AMP to phosphorylase b, the enzyme activity as well as the molar absorption coefficient of the absorption difference spectra studied show no discontinuity with temperature from 5 to 30°C.
Biopolymers, 1998
In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and n... more In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and neutral, has been carried out. The preferred conformations were determined by means of ab initio and semiempirical quantum, together with empirical force field calculations. The AMBER* force field and the 6-31 / G** and 6-31G** ab initio levels give rise to a coincident minimum energy structure, which, on the other hand, differs from that determined by AM1, 3-21 / G, and 3-21G. The solvent effect on the different charged and neutral conformations have been considered through the AMSOL semiempirical method. A quantification regarding the structural similarities between the different dipeptide conformations and the ampicillin has been performed. The results show that the best overlay is attained by the minimum structure energy obtained by using the 6-31
International Journal of Biological Macromolecules, 1985
Absorption difference spectra of phosphorylase b when AMP binds to its high affinity site have be... more Absorption difference spectra of phosphorylase b when AMP binds to its high affinity site have been studied at 25°C and pH 6.9; the absorbance changes show linearity as a function of the amount of phophorylase b-AMP complex present in solution. The negative regions of these spectra have been interpreted by assigning the hypochromic effect in the absorption band of AMP to stacking of the adenine ring with an aromatic ring from some tyrosine and/or tryptophan residues. On the other hand, the positive region of the difference spectrum induced by binding of AMP to its high affinity site can be simulated assuming that six tyrosines and one or two tryptophans per monomer are embedded in a highly hydrophobic environment.
Biopolymers, 1998
In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and n... more In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and neutral, has been carried out. The preferred conformations were determined by means of ab initio and semiempirical quantum, together with empirical force field calculations. The AMBER* force field and the 6-31 / G** and 6-31G** ab initio levels give rise to a coincident minimum energy structure, which, on the other hand, differs from that determined by AM1, 3-21 / G, and 3-21G. The solvent effect on the different charged and neutral conformations have been considered through the AMSOL semiempirical method. A quantification regarding the structural similarities between the different dipeptide conformations and the ampicillin has been performed. The results show that the best overlay is attained by the minimum structure energy obtained by using the 6-31
International Journal of Biological Macromolecules, 1985
Equilibrium dialysis measurements have been performed at several temperatures, ranging from 5 to ... more Equilibrium dialysis measurements have been performed at several temperatures, ranging from 5 to 30°C, to calculate the binding constants of AMP to phosphorylase b (EC 2.4.1.1). AH=-lOkcal/mol and AS = -16.4 e.u. have been obtained for the binding process. Measurements of enzymatic activity have been performed in the same temperature range. An activation energy of16 kcal has been calculated for the enzymecatalysed reaction. Absorption difference spectra induced by AMP in phosphorylase b when AMP is bound to its high affinity site have also been carried out at these temperatures. The equilibrium constant for the binding of AMP to phosphorylase b, the enzyme activity as well as the molar absorption coefficient of the absorption difference spectra studied show no discontinuity with temperature from 5 to 30°C.
Biopolymers, 1998
In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and n... more In this article a conformational analysis of the D-alanyl-D-alanine dipeptide, both charged and neutral, has been carried out. The preferred conformations were determined by means of ab initio and semiempirical quantum, together with empirical force field calculations. The AMBER* force field and the 6-31 / G** and 6-31G** ab initio levels give rise to a coincident minimum energy structure, which, on the other hand, differs from that determined by AM1, 3-21 / G, and 3-21G. The solvent effect on the different charged and neutral conformations have been considered through the AMSOL semiempirical method. A quantification regarding the structural similarities between the different dipeptide conformations and the ampicillin has been performed. The results show that the best overlay is attained by the minimum structure energy obtained by using the 6-31