I need any recommendations ...
borovok at POST.TAU.AC.IL
Wed Jan 3 09:33:54 EST 1996
I would like to ask you help me in seasrching any nice (possibly modern)
review and other sources concerning a phenomenon of an iron binding by
proteins. It's not very easy question.
My case: I am a genetist and at present deal with a genetical analysis of
Isopenicillin N Synthase (IPNS) from Streptomyces. It is non heme enzyme and
requires Fe(II) as a cofactor. We did make mutations which switch off an
activity of this enzyme and found all potential ligands which involved in
iron-binding to form an active site; the same ligands have been shown
recently in Nature (22 June, 95) for another IPNS from Aspergillus nidulans
by use of 3D structure. So far this 3D structure is not placed in PDB. We
and they did show there are two histidines and one aspartic acid those are
ligands of this kind of dioxygenases. But in our case the 'total', triple,
mutant IPNS protein with all switched off ligands did ... binds iron also
very well. This unspecific (?) iron binding is same for both wild type
protein and any mutant protein. This binding is very strong and an
iron-IPNS-protein complex is running through Sephadex G-25 Fine keeping the
same final ratio between iron and any mutant or wild type IPNS proteins.
My additional questions are:
a. Which reason(s) could explain(s) nicely our observation of an
'unspecific' iron binding by Isopenicillin N Synthase protein?
b. Which kind of possible 'preventive' methods could be used to except
such 'unspecific' iron binding by Isopenicillin N Synthase protein?
Please, answering me, remember that my speciality is genetics! Please,
be without very hard comments concerning my 'report'!
Thank anybody in advance for any information.
borovok at ccsg.tau.ac.il
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