[RASMB] dn/dc

[Mattia Rocco]

I agree with John regarding the dn/dc, but maybe the absolute calibration of the instrument could also be an issue... or the on-line concentration determination... as Andrew Leech pointed out this morning, do you recover the approximately correct molecular weight for, say, BSA?
 
Mattia

________________________________

From: RASMB on behalf of John Philo
Sent: Thu 3/17/2016 4:22 PM
To: 'Stephen McLaughlin'; rasmb at rasmb.org
Subject: Re: [RASMB] dn/dc



Stephen, I think it is unlikely the dn/dc for your protein differs by more than 5% from your calculation. If there is a "major" discrepancy then calibration is not the issue. 

John

 

-----Original Message-----
From: RASMB [mailto:rasmb-bounces at list.rasmb.org] On Behalf Of Stephen McLaughlin
Sent: Thursday, March 17, 2016 5:08 AM
To: Mattia Rocco <mattia.rocco at hsanmartino.it>
Cc: rasmb at rasmb.org
Subject: Re: [RASMB] dn/dc

 

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 <mailto: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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