[RASMB] very slow sedimenting protein

[Arthur Rowe]

Hi Virgil -

A random coil of M = 15.570 kD would sediment more slowly than a native
protein, but nothing like as slowly as you describe.

There isn't any possibility, is there, that the metal is tightening up (and
hence stabilising) the structure of protein which is prone to proteolytic
attack, is there ?

Regards

Arthur

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Arthur J Rowe
Professor of Biomolecular Technology
NCMH Business Centre
University of Nottingham
School of Biosciences
Sutton Bonington
Leicestershire LE12 5RD   UK

Tel:        +44 (0)115 951 6156
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From: Virgil Schirf <schirfv at bioc09.v19.uthscsa.edu>
Organization: AUC Core Facility
Date: Wed, 31 Jul 2002 10:06:56 -0500
To: "rasmb at server1.bbri.org" <rasmb at server1.bbri.org>
Subject: [RASMB] very slow sedimenting protein


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Good morning!

We have a protein with a Mr = 15570 (and was expected to form a tight
dimer) and performed a sedimentation velocity experiment. After 4 hours
at 60000 rpm, a slight shoulder formed as the boundary, but it never
cleared the meniscus. It was run at 20 deg C in 100 mM phosphate buffer.
The metal containing form of the protein ran as expected. The question
is: why does the apo form of the protein not sediment? One theory is
that it exists as a random coil without secondary structure. Does anyone
have any experience with a protein such as this.

Thanks to all,

Virgil
-- 
Virgil Schirf
Department of Biochemistry, Rm 535C
The University of Texas Health Science Center at San Antonio
7703 Floyd Curl Dr.
San Antonio TX 78229
email: schirfv at biochem.uthscsa.edu
Voicemail: (210) 567-6590  FAX: (210)567-6595
http://cauma.uthscsa.edu

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