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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Dear RASMB,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>this question is in relation to f/f0. f/f0=(f/f)hydration*volume-asymetry and is also equal to s-sphere/s20w as per Lebowitz et. al. (Protein Science 2002). I have two questions.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>1. what is the physical meaning of (f/f)hydration? Does this describe a shape parameter of the un-hydrated macromolecule?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>2. v-bar(solvent) is a factor in the volume-asymmetry term. How is this related to the solvent density?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>I also have a third related question. Estimation of the axial ratio seems to require some knowledge of s-0, the sedimentation value extrapolated to zero macromolecule concentration. Could someone please point me at an appropriate reference describing how this is estimated in c(s).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Many thanks in advance, for this and all of my previous inquiries.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Best regards,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>John Sumida, Ph.D.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><a href="http://depts.washington.edu/cidb4bio/index.shtml"><span style='color:windowtext'>Analytical Biopharmacy Core Facility</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>University of Washington<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'><a href="http://www.moles.washington.edu/"><span style='color:windowtext'>Molecular Engineering & Sciences Institute, G22</span></a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>3946 West Stevens Way NE<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Courier New"'>Seattle WA 98195-1653<o:p></o:p></span></p></div><p class=MsoNormal style='text-autospace:none'><span style='color:black'><o:p> </o:p></span></p></div></body></html>