[RASMB] dn/dc

[Andrew Leech]

Hi Stephen,

How small is "small"? I have found that small proteins (<~12 kDa) tend
to be less reliable possibly because the atomic composition of the
protein and its accompaniments deviate from the "averages" applicable
to larger entities. Also the LS signals get weak, so high protein
concentration helps in the SECMALLS, unless aggregation starts to
happen. Do you have a similar size control (perhaps non-zinc bound
protein) to compare?

All the best,

Andrew


On 17/03/2016 12:08, Stephen McLaughlin wrote:
> Dear Mattia,
>
> at the minute, it would be good to know if the dn/dc increases or decreases  and roughy how much. There is a significant discrepancy between the molar mass measured by SEC-MALS and the expected mass from mass-spec.
>
> Best
>
> Stephen
>
>
>
> On 17 Mar 2016, at 09:53, Mattia Rocco wrote:
>
>> Dear Stephen,
>>
>> it likely will. But calculating a dn/dc is not that reliable anyway... and what's the level of precision you need, after all?
>>
>> Best - Mattia
>>
>> ________________________________
>>
>> From: RASMB on behalf of Stephen McLaughlin
>> Sent: Thu 3/17/2016 10:40 AM
>> To: rasmb at rasmb.org
>> Subject: [RASMB] dn/dc
>>
>>
>> Dear all,
>>
>> I have a small three fingered Zn binding protein.  Will the presence of Zn ions affect the refractive increment that can be caluculated from sequence?
>>
>>
>> Best
>>
>> Stephen
>>
>>
>> ______________________________
>>
>> Stephen McLaughlin, Ph.D.
>>
>> Biophysics
>> MRC Laboratory of Molecular Biology
>> Francis Crick Avenue
>> Cambridge Biomedical Campus
>> Cambridge, CB2 0QH
>>
>> Tel.: +44 (0) 1223 267891 (office)
>>
>> Email:stephenm at mrc-lmb.cam.ac.uk
>> _____________________________
>>
>>
>>
>>
>>
>>
>>
>
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-- 
Dr Andrew Leech                   *  Laboratory Head
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