[RASMB] another vbar question

[HGSR (Holger Martin Strauss)]

Hello yall,

Wow, vbar trending?!

I actually have a question regarding the salt-dependency of the vbar. We are working with peptides modified with some organic linkers and a diacid (between C4-C50, to give a range). We measure the droh/dc (DMA5000) at different concentrations and calculate the vbar. Controls OK, concentration accurate and measurements reproducible, buffer dialysed. Salt-concentration is varied (NaCl, 5-1500 mM-ish). Turns out the vbar is considerably different at high salt. (And so is the self-association, btw.) No detergents or denaturants, just some additional phosphate for buffering, besides the NaCl.

-       How can this be rationalised structurally?
-       Any tests when droh/dc is more appropriate for Mw /sigma than vbar?
-       Other examples in the literature for peptides?
-       Any general comments/anectodes/remarks?

Cheers,

Holger

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