quote:
When mutations happen, there is no new genetic infomationt that occurs.
New enzymes are formed by mutations, such as the nylong digesting enzyme ([url=http://www.nmsr.org/nylon.htm]Reference) or the new malarial resistance hemoglobin gene (
Referenc). If that isn't new information then I don't know what is.
quote:
But all these mutations reduce the information in the gene by making a protein less specific.
Except in cases where mutations make a protein more specific and more active:
Eur J Biochem. 2004 Nov;271(21):4169-77. Related Articles, Links
Investigation of the substrate specificity of a beta-glycosidase from Spodoptera frugiperda using site-directed mutagenesis and bioenergetics analysis.
Marana SR, Andrade EH, Ferreira C, Terra WR.
Departamento de Bioquimica, Instituto de Quimica, Universidade de Sao Paulo, Sao Paulo, Brazil.
The specificity of the Spodoptera frugiperda digestive beta-glycosidase (Sfbetagly50) for fucosides, glucosides and galactosides is determined by noncovalent interactions of glycone 6-OH and glycone 4-OH with the active-site residues Q39 and E451.
Site-directed mutagenesis and enzyme steady-state kinetics were described, showing that replacement of E451 with glutamine increased the preference of Sfbetagly50 for glucosides in comparison to galactosides, whereas replacing E451 with serine had the opposite effect. In contrast, the replacement of E451 with aspartate did not change Sfbetagly50 specificity. The energy of the interactions formed by these different residues with the axial and equatorial glycone 4-OH were also measured, showing that the increase in preference for galactosides resulted from a larger energy decrease in the interaction with equatorial 4-OH than with axial 4-OH (22.6 vs. 13.9 kJ.mol(-1)), whereas the increase in preference for glucosides was caused by an energy reduction in the interaction with the axial 4-OH (5.1 kJ.mol(-1)).
The introduction of glutamine at position 451 or of asparagine at position 39 increased the preference of Sfbetagly50 for fucosides in comparison to galactosides, whereas the presence of aspartate or serine at position 451 had less effect on this preference. The hydrolysis of fucosides was favored because glutamine at position 451 increased a steric hindrance with 6-OH of 7.1 kJ.mol(-1) and asparagine at position 39 disrupted a favorable interaction with this same hydroxyl. In conclusion, it is proposed that the specificity of new beta-glycosidase mutants can be predicted by combining and adding energy of the enzyme-substrate interactions evaluated in the present study. emphasis mine
Arch Biochem Biophys. 2004 Oct 15;430(2):185-90. Related Articles, Links
Kinetic studies and site-directed mutagenesis of Escherichia coli agmatinase. A role for Glu274 in binding and correct positioning of the substrate guanidinium group.
Carvajal N, Orellana MS, Salas M, Enriquez P, Alarcon R, Uribe E, Lopez V.
Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Casilla 160-C, Chile. ncarvaja@udec.cl
The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with respect to agmatine and their bindings to the enzyme were not mutually exclusive. By site-directed mutagenesis, the E274A variant exhibiting about 1-2% of wild-type activity was obtained.
Mutation produced a moderate, but significant, increase in the Km value for agmatine (from 1.1 +/- 0.2 mM to 6.3 +/- 0.3 mM) and the Ki value for competitive inhibition by Gdn+ (from 15.0 +/- 0.1 mM to 44.2 +/- 2.1 mM), but the Ki value for putrescine inhibition (2.8 +/- 0.2 mM) was not altered. The tryptophan fluorescence properties (lambdamax = 342 nm) and circular dichroism spectra were not significantly altered by the Glu274 --> Ala mutation. The dimeric structure of the enzyme was also maintained. We conclude that Glu274 is involved in binding and positioning of the guanidinium moiety of the substrate for efficient catalysis. A kinetic mechanism involving rapid equilibrium random release of products is proposed for E. coli agmatinase. emphasis mine
quote:
Indeed, all mutations studied destroy information.
Then how does Spetner explain hemoglobic C and the nylon bug?
quote:
None of them can serve as an example of a mutation that can lead to the large changes of macroevolution. ... Whoever thinks macroevolution can be made by mutations that lose information is like the merchant who lost a little money on every sale but thought he could make it up on volume.
I have given you numerous examples of mutations adding information. Do or do these examples demonstrate an increase in information? If not, then could you give me an example of what an increase of information looks like at the DNA level?Reference) or the new malarial resistance hemoglobin gene (
Referenc). If that isn't new information then I don't know what is.
quote:
But all these mutations reduce the information in the gene by making a protein less specific.
Except in cases where mutations make a protein more specific and more active:
Eur J Biochem. 2004 Nov;271(21):4169-77. Related Articles, Links
Investigation of the substrate specificity of a beta-glycosidase from Spodoptera frugiperda using site-directed mutagenesis and bioenergetics analysis.
Marana SR, Andrade EH, Ferreira C, Terra WR.
Departamento de Bioquimica, Instituto de Quimica, Universidade de Sao Paulo, Sao Paulo, Brazil.
The specificity of the Spodoptera frugiperda digestive beta-glycosidase (Sfbetagly50) for fucosides, glucosides and galactosides is determined by noncovalent interactions of glycone 6-OH and glycone 4-OH with the active-site residues Q39 and E451.
Site-directed mutagenesis and enzyme steady-state kinetics were described, showing that replacement of E451 with glutamine increased the preference of Sfbetagly50 for glucosides in comparison to galactosides, whereas replacing E451 with serine had the opposite effect. In contrast, the replacement of E451 with aspartate did not change Sfbetagly50 specificity. The energy of the interactions formed by these different residues with the axial and equatorial glycone 4-OH were also measured, showing that the increase in preference for galactosides resulted from a larger energy decrease in the interaction with equatorial 4-OH than with axial 4-OH (22.6 vs. 13.9 kJ.mol(-1)), whereas the increase in preference for glucosides was caused by an energy reduction in the interaction with the axial 4-OH (5.1 kJ.mol(-1)).
The introduction of glutamine at position 451 or of asparagine at position 39 increased the preference of Sfbetagly50 for fucosides in comparison to galactosides, whereas the presence of aspartate or serine at position 451 had less effect on this preference. The hydrolysis of fucosides was favored because glutamine at position 451 increased a steric hindrance with 6-OH of 7.1 kJ.mol(-1) and asparagine at position 39 disrupted a favorable interaction with this same hydroxyl. In conclusion, it is proposed that the specificity of new beta-glycosidase mutants can be predicted by combining and adding energy of the enzyme-substrate interactions evaluated in the present study. emphasis mine
Arch Biochem Biophys. 2004 Oct 15;430(2):185-90. Related Articles, Links
Kinetic studies and site-directed mutagenesis of Escherichia coli agmatinase. A role for Glu274 in binding and correct positioning of the substrate guanidinium group.
Carvajal N, Orellana MS, Salas M, Enriquez P, Alarcon R, Uribe E, Lopez V.
Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Casilla 160-C, Chile. ncarvaja@udec.cl
The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with respect to agmatine and their bindings to the enzyme were not mutually exclusive. By site-directed mutagenesis, the E274A variant exhibiting about 1-2% of wild-type activity was obtained.
Mutation produced a moderate, but significant, increase in the Km value for agmatine (from 1.1 +/- 0.2 mM to 6.3 +/- 0.3 mM) and the Ki value for competitive inhibition by Gdn+ (from 15.0 +/- 0.1 mM to 44.2 +/- 2.1 mM), but the Ki value for putrescine inhibition (2.8 +/- 0.2 mM) was not altered. The tryptophan fluorescence properties (lambdamax = 342 nm) and circular dichroism spectra were not significantly altered by the Glu274 --> Ala mutation. The dimeric structure of the enzyme was also maintained. We conclude that Glu274 is involved in binding and positioning of the guanidinium moiety of the substrate for efficient catalysis. A kinetic mechanism involving rapid equilibrium random release of products is proposed for E. coli agmatinase. emphasis mine
quote:
Indeed, all mutations studied destroy information.
Then how does Spetner explain hemoglobic C and the nylon bug?
quote:
None of them can serve as an example of a mutation that can lead to the large changes of macroevolution. ... Whoever thinks macroevolution can be made by mutations that lose information is like the merchant who lost a little money on every sale but thought he could make it up on volume.
I have given you numerous examples of mutations adding information. Do or do these examples demonstrate an increase in information? If not, then could you give me an example of what an increase of information looks like at the DNA level?
[]Reference) or the new malarial resistance hemoglobin gene (
Referenc). If that isn't new information then I don't know what is.
quote:
But all these mutations reduce the information in the gene by making a protein less specific.
Except in cases where mutations make a protein more specific and more active:
Eur J Biochem. 2004 Nov;271(21):4169-77. Related Articles, Links
Investigation of the substrate specificity of a beta-glycosidase from Spodoptera frugiperda using site-directed mutagenesis and bioenergetics analysis.
Marana SR, Andrade EH, Ferreira C, Terra WR.
Departamento de Bioquimica, Instituto de Quimica, Universidade de Sao Paulo, Sao Paulo, Brazil.
The specificity of the Spodoptera frugiperda digestive beta-glycosidase (Sfbetagly50) for fucosides, glucosides and galactosides is determined by noncovalent interactions of glycone 6-OH and glycone 4-OH with the active-site residues Q39 and E451.
Site-directed mutagenesis and enzyme steady-state kinetics were described, showing that replacement of E451 with glutamine increased the preference of Sfbetagly50 for glucosides in comparison to galactosides, whereas replacing E451 with serine had the opposite effect. In contrast, the replacement of E451 with aspartate did not change Sfbetagly50 specificity. The energy of the interactions formed by these different residues with the axial and equatorial glycone 4-OH were also measured, showing that the increase in preference for galactosides resulted from a larger energy decrease in the interaction with equatorial 4-OH than with axial 4-OH (22.6 vs. 13.9 kJ.mol(-1)), whereas the increase in preference for glucosides was caused by an energy reduction in the interaction with the axial 4-OH (5.1 kJ.mol(-1)).
The introduction of glutamine at position 451 or of asparagine at position 39 increased the preference of Sfbetagly50 for fucosides in comparison to galactosides, whereas the presence of aspartate or serine at position 451 had less effect on this preference. The hydrolysis of fucosides was favored because glutamine at position 451 increased a steric hindrance with 6-OH of 7.1 kJ.mol(-1) and asparagine at position 39 disrupted a favorable interaction with this same hydroxyl. In conclusion, it is proposed that the specificity of new beta-glycosidase mutants can be predicted by combining and adding energy of the enzyme-substrate interactions evaluated in the present study. emphasis mine
Arch Biochem Biophys. 2004 Oct 15;430(2):185-90. Related Articles, Links
Kinetic studies and site-directed mutagenesis of Escherichia coli agmatinase. A role for Glu274 in binding and correct positioning of the substrate guanidinium group.
Carvajal N, Orellana MS, Salas M, Enriquez P, Alarcon R, Uribe E, Lopez V.
Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Casilla 160-C, Chile. ncarvaja@udec.cl
The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with respect to agmatine and their bindings to the enzyme were not mutually exclusive. By site-directed mutagenesis, the E274A variant exhibiting about 1-2% of wild-type activity was obtained.
Mutation produced a moderate, but significant, increase in the Km value for agmatine (from 1.1 +/- 0.2 mM to 6.3 +/- 0.3 mM) and the Ki value for competitive inhibition by Gdn+ (from 15.0 +/- 0.1 mM to 44.2 +/- 2.1 mM), but the Ki value for putrescine inhibition (2.8 +/- 0.2 mM) was not altered. The tryptophan fluorescence properties (lambdamax = 342 nm) and circular dichroism spectra were not significantly altered by the Glu274 --> Ala mutation. The dimeric structure of the enzyme was also maintained. We conclude that Glu274 is involved in binding and positioning of the guanidinium moiety of the substrate for efficient catalysis. A kinetic mechanism involving rapid equilibrium random release of products is proposed for E. coli agmatinase. emphasis mine
quote:
Indeed, all mutations studied destroy information.
Then how does Spetner explain hemoglobic C and the nylon bug?
quote:
None of them can serve as an example of a mutation that can lead to the large changes of macroevolution. ... Whoever thinks macroevolution can be made by mutations that lose information is like the merchant who lost a little money on every sale but thought he could make it up on volume.
I have given you numerous examples of mutations adding information. Do or do these examples demonstrate an increase in information? If not, then could you give me an example of what an increase of information looks like at the DNA level?Reference) or the new malarial resistance hemoglobin gene (
Referenc). If that isn't new information then I don't know what is.
quote:
But all these mutations reduce the information in the gene by making a protein less specific.
Except in cases where mutations make a protein more specific and more active:
Eur J Biochem. 2004 Nov;271(21):4169-77. Related Articles, Links
Investigation of the substrate specificity of a beta-glycosidase from Spodoptera frugiperda using site-directed mutagenesis and bioenergetics analysis.
Marana SR, Andrade EH, Ferreira C, Terra WR.
Departamento de Bioquimica, Instituto de Quimica, Universidade de Sao Paulo, Sao Paulo, Brazil.
The specificity of the Spodoptera frugiperda digestive beta-glycosidase (Sfbetagly50) for fucosides, glucosides and galactosides is determined by noncovalent interactions of glycone 6-OH and glycone 4-OH with the active-site residues Q39 and E451.
Site-directed mutagenesis and enzyme steady-state kinetics were described, showing that replacement of E451 with glutamine increased the preference of Sfbetagly50 for glucosides in comparison to galactosides, whereas replacing E451 with serine had the opposite effect. In contrast, the replacement of E451 with aspartate did not change Sfbetagly50 specificity. The energy of the interactions formed by these different residues with the axial and equatorial glycone 4-OH were also measured, showing that the increase in preference for galactosides resulted from a larger energy decrease in the interaction with equatorial 4-OH than with axial 4-OH (22.6 vs. 13.9 kJ.mol(-1)), whereas the increase in preference for glucosides was caused by an energy reduction in the interaction with the axial 4-OH (5.1 kJ.mol(-1)).
The introduction of glutamine at position 451 or of asparagine at position 39 increased the preference of Sfbetagly50 for fucosides in comparison to galactosides, whereas the presence of aspartate or serine at position 451 had less effect on this preference. The hydrolysis of fucosides was favored because glutamine at position 451 increased a steric hindrance with 6-OH of 7.1 kJ.mol(-1) and asparagine at position 39 disrupted a favorable interaction with this same hydroxyl. In conclusion, it is proposed that the specificity of new beta-glycosidase mutants can be predicted by combining and adding energy of the enzyme-substrate interactions evaluated in the present study. emphasis mine
Arch Biochem Biophys. 2004 Oct 15;430(2):185-90. Related Articles, Links
Kinetic studies and site-directed mutagenesis of Escherichia coli agmatinase. A role for Glu274 in binding and correct positioning of the substrate guanidinium group.
Carvajal N, Orellana MS, Salas M, Enriquez P, Alarcon R, Uribe E, Lopez V.
Departamento de Bioquimica y Biologia Molecular, Facultad de Ciencias Biologicas, Universidad de Concepcion, Casilla 160-C, Chile. ncarvaja@udec.cl
The interaction of Escherichia coli agmatinase (EC 3.5.3.11) with the substrate guanidinium group was investigated by kinetic and site-directed mutagenesis studies. Putrescine and guanidinium ions (Gdn+) were slope-linear, competitive inhibitors with respect to agmatine and their bindings to the enzyme were not mutually exclusive. By site-directed mutagenesis, the E274A variant exhibiting about 1-2% of wild-type activity was obtained.
Mutation produced a moderate, but significant, increase in the Km value for agmatine (from 1.1 +/- 0.2 mM to 6.3 +/- 0.3 mM) and the Ki value for competitive inhibition by Gdn+ (from 15.0 +/- 0.1 mM to 44.2 +/- 2.1 mM), but the Ki value for putrescine inhibition (2.8 +/- 0.2 mM) was not altered. The tryptophan fluorescence properties (lambdamax = 342 nm) and circular dichroism spectra were not significantly altered by the Glu274 --> Ala mutation. The dimeric structure of the enzyme was also maintained. We conclude that Glu274 is involved in binding and positioning of the guanidinium moiety of the substrate for efficient catalysis. A kinetic mechanism involving rapid equilibrium random release of products is proposed for E. coli agmatinase. emphasis mine
quote:
Indeed, all mutations studied destroy information.
Then how does Spetner explain hemoglobic C and the nylon bug?
quote:
None of them can serve as an example of a mutation that can lead to the large changes of macroevolution. ... Whoever thinks macroevolution can be made by mutations that lose information is like the merchant who lost a little money on every sale but thought he could make it up on volume.
I have given you numerous examples of mutations adding information. Do or do these examples demonstrate an increase in information? If not, then could you give me an example of what an increase of information looks like at the DNA level?
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