1sgk
From Proteopedia
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| - | [[Image:1sgk.gif|left|200px]]<br /> | + | [[Image:1sgk.gif|left|200px]]<br /><applet load="1sgk" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1sgk" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1sgk, resolution 2.3Å" /> | caption="1sgk, resolution 2.3Å" /> | ||
'''NUCLEOTIDE-FREE DIPHTHERIA TOXIN'''<br /> | '''NUCLEOTIDE-FREE DIPHTHERIA TOXIN'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1SGK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Corynephage_beta Corynephage beta]. Active as [http://en.wikipedia.org/wiki/NAD(+)--diphthamide_ADP-ribosyltransferase NAD(+)--diphthamide ADP-ribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.36 2.4.2.36] | + | 1SGK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Corynephage_beta Corynephage beta]. Active as [http://en.wikipedia.org/wiki/NAD(+)--diphthamide_ADP-ribosyltransferase NAD(+)--diphthamide ADP-ribosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.2.36 2.4.2.36] Known structural/functional Site: <scene name='pdbsite=CAT:GLU 148 Active-Site Residue Involved In Catalysis Of Adp ...'>CAT</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1SGK OCA]. |
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 18:00:05 2007'' |
Revision as of 15:50, 18 December 2007
|
NUCLEOTIDE-FREE DIPHTHERIA TOXIN
Overview
The crystal structure of diphtheria toxin (DT) in the absence of, nucleotide (nucleotide-free DT) has been determined at 2.3 A resolution to, a crystallographic R factor and free R factor of 18.2 and 28.2%, respectively. A comparison of this structure to the previously determined, structures of DT in complex with adenyly(3'-5')uridine monophosphate, (ApUp) and DT in complex with nicotinamide adenine dinucleotide (NAD), reveals that there are no significant movements of the two subdomains of, the catalytic (C) domain associated with dinucleotide binding. The side, chains of six residues within the active-site cleft, including Tyr65, Pro38, Tyr27, Thr23, Glu148, and Tyr54, show movements of up to 3 A upon, dinucleotide binding. In the structure of nucleotide-free DT, the, active-site loop residues 39-47 of the C domain are well ordered and, extend over the active-site cleft in approximately the same position as in, the structure of DT in complex with ApUp. This is in contrast to the, structure of the DT-NAD complex, in which the active-site loop is, disordered. On the basis of a comparison of the nucleotide-free and, NAD-bound DT structures, we suggest that the interaction of NAD with Pro38, and also possibly Tyr54 and Trp153 could disrupt the network of hydrogen, bonds that stabilizes the position of the active-site loop over the, active-site cleft, allowing this loop to become disordered. This may be an, important step in binding of the C domain of DT to its substrate, elongation factor-2.
About this Structure
1SGK is a Single protein structure of sequence from Corynephage beta. Active as NAD(+)--diphthamide ADP-ribosyltransferase, with EC number 2.4.2.36 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Crystal structure of nucleotide-free diphtheria toxin., Bell CE, Eisenberg D, Biochemistry. 1997 Jan 21;36(3):481-8. PMID:9012663
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