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<TITLE>Re: [RASMB] very slow sedimenting protein</TITLE>
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Hi Virgil -<BR>
<BR>
A random coil of M = 15.570 kD would sediment more slowly than a native protein, but nothing like as slowly as you describe.<BR>
<BR>
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 ?<BR>
<BR>
Regards<BR>
<BR>
Arthur<BR>
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<BLOCKQUOTE><B>From: </B>Virgil Schirf <schirfv@bioc09.v19.uthscsa.edu><BR>
<B>Organization: </B>AUC Core Facility<BR>
<B>Date: </B>Wed, 31 Jul 2002 10:06:56 -0500<BR>
<B>To: </B>"rasmb@server1.bbri.org" <rasmb@server1.bbri.org><BR>
<B>Subject: </B>[RASMB] very slow sedimenting protein<BR>
<BR>
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<BR>
Good morning!<BR>
<BR>
We have a protein with a Mr = 15570 (and was expected to form a tight <BR>
dimer) and performed a sedimentation velocity experiment. After 4 hours <BR>
at 60000 rpm, a slight shoulder formed as the boundary, but it never <BR>
cleared the meniscus. It was run at 20 deg C in 100 mM phosphate buffer. <BR>
The metal containing form of the protein ran as expected. The question <BR>
is: why does the apo form of the protein not sediment? One theory is <BR>
that it exists as a random coil without secondary structure. Does anyone <BR>
have any experience with a protein such as this.<BR>
<BR>
Thanks to all,<BR>
<BR>
Virgil<BR>
-- <BR>
Virgil Schirf<BR>
Department of Biochemistry, Rm 535C<BR>
The University of Texas Health Science Center at San Antonio<BR>
7703 Floyd Curl Dr.<BR>
San Antonio TX 78229<BR>
email: schirfv@biochem.uthscsa.edu<BR>
Voicemail: (210) 567-6590 FAX: (210)567-6595<BR>
http://cauma.uthscsa.edu<BR>
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