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4 bytes added ,  15:40, November 20, 2007
→‎Gain-of-function mutations: Addition of HIV-1 M Subtype D gated sodium cation channel.
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{{QuoteBox|This is good evidence that natural selection plays a part in maintaining a higher frequency of this carrier state. If you are resistant to malaria, you are more likely to survive to pass on your genes. Nevertheless, it is a defect, not an increase in complexity or an improvement in function which is being selected for, and having more carriers in the population means that there will be more people suffering from this terrible [[disease]].<ref>[http://www.creationontheweb.com/content/view/901/ Sickle-cell anemia does not prove evolution!], ''Creation'' 16(2):40–41, March 1994.</ref>}}
 
{{QuoteBox|This is good evidence that natural selection plays a part in maintaining a higher frequency of this carrier state. If you are resistant to malaria, you are more likely to survive to pass on your genes. Nevertheless, it is a defect, not an increase in complexity or an improvement in function which is being selected for, and having more carriers in the population means that there will be more people suffering from this terrible [[disease]].<ref>[http://www.creationontheweb.com/content/view/901/ Sickle-cell anemia does not prove evolution!], ''Creation'' 16(2):40–41, March 1994.</ref>}}
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'''HIV-1 M subtype D's Na+ viroporin''', is known as an example of a Gain-of-Function mutation due to the viroporin being gated and specific to Na+ cations.  A viroporin is an ion channel that allows for the movment of ions from one side of a membrane to another.  A gated channel has an additional feature which closes the channel to prevent "leaking" of ions across the membrane.  In this example the clades before HIV-1 M did not have this viroporin.  To go from an ordinary viroporin's original form to the multisubunit structure with a new function required the development of a new binding site, which involves more than a single amino acid substitution<ref>Paul et al. (1998) Mutational Analysis of the Human Immunodeficiency Virus Type 1 Vpu Transmembrane Domain That Promotes the Enhanced Release of Virus-Like Particles from the Plasma Membrane of Mammalian Cells. J Virol, 72 (2): 1270.</ref>. Not just any binding site will do, for a mass of agglomerated protein would occur, not an ion channel with ion selectivity. As such, HIV-1 M's viroporin is a gated ion channel, not just a hole punched in the membrane, with a specific amino acid responsible for the gating<ref>Mehnert T, et al., Biophysical characterization of Vpu from HIV-1 suggests a channel-pore dualism. Proteins. 2007 Oct 1; doi: 10.1002/prot.21642.</ref>. What is important is that this mutation is beneficial to the virus; it increases viral particle release, spreading HIV more efficiently<ref>Paul et al. (1998) Mutational Analysis of the Human Immunodeficiency Virus Type 1 Vpu Transmembrane Domain That Promotes the Enhanced Release of Virus-Like Particles from the Plasma Membrane of Mammalian Cells. J Virol, 72 (2): 1270.</ref>.
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'''HIV-1 M subtype D's Na+ viroporin''', is known as an example of a Gain-of-Function mutation due to the viroporin being gated and specific to Na+ cations.  A viroporin is an ion channel that allows for the movement of ions from one side of a membrane to another.  A gated channel has an additional feature which closes the channel to prevent "leaking" of ions across the membrane.  In this example the HIV types before HIV-1 M did not have this viroporin.  To go from an ordinary viroporin's original form to the multisubunit structure with a new function required the development of a new binding site, which involves more than a single amino acid substitution<ref>Paul et al. (1998) Mutational Analysis of the Human Immunodeficiency Virus Type 1 Vpu Transmembrane Domain That Promotes the Enhanced Release of Virus-Like Particles from the Plasma Membrane of Mammalian Cells. J Virol, 72 (2): 1270.</ref>. Not just any binding site will do, for a mass of agglomerated protein would occur, not an ion channel with ion selectivity. As such, HIV-1 M's viroporin is a gated ion channel, not just a hole punched in the membrane, with a specific amino acid responsible for the gating<ref>Mehnert T, et al., Biophysical characterization of Vpu from HIV-1 suggests a channel-pore dualism. Proteins. 2007 Oct 1; doi: 10.1002/prot.21642.</ref>. What is important is that this mutation is beneficial to the virus; it increases viral particle release, spreading HIV more efficiently<ref>Paul et al. (1998) Mutational Analysis of the Human Immunodeficiency Virus Type 1 Vpu Transmembrane Domain That Promotes the Enhanced Release of Virus-Like Particles from the Plasma Membrane of Mammalian Cells. J Virol, 72 (2): 1270.</ref>.
    
==Mutatations and the Theory of Evolution==
 
==Mutatations and the Theory of Evolution==
nsJudgesRO, nsJudgesRW, nsJudges_talkRO, nsJudges_talkRW
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