1sxq
From Proteopedia
(New page: 200px<br /><applet load="1sxq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1sxq, resolution 1.8Å" /> '''BGT in complex with a...) |
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| - | [[Image:1sxq.gif|left|200px]]<br /><applet load="1sxq" size=" | + | [[Image:1sxq.gif|left|200px]]<br /><applet load="1sxq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1sxq, resolution 1.8Å" /> | caption="1sxq, resolution 1.8Å" /> | ||
'''BGT in complex with a 13mer DNA containing a central C:G base pair and UDP'''<br /> | '''BGT in complex with a 13mer DNA containing a central C:G base pair and UDP'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Beta-glucosyltransferase (BGT) is a DNA-modifying enzyme and a | + | Beta-glucosyltransferase (BGT) is a DNA-modifying enzyme and a glycosyltransferase. This inverting enzyme transfers glucose from UDP-glucose to the 5-hydroxymethyl cytosine bases of T4 phage DNA. From previous structural analyses we showed that Asp-100 and Asn-70 were, respectively, the catalytic base and the key residue for specific DNA recognition (Lariviere, L., Gueguen-Chaignon, V., and Morera, S. (2003) J. Mol. Biol. 330, 1077-1086). Here, we supply biochemical evidence supporting their essential roles in catalysis. We have also shown previously that BGT uses a base-flipping mechanism to access 5-hydroxymethyl cytosine (Lariviere, L., and Morera, S. (2002) J. Mol. Biol. 324, 483-490). Whether it is an active or a passive process remains unclear, as is the case for all DNA cleaving and modifying enzymes. Here, we report two crystal structures: (i) BGT in complex with a 13-mer DNA containing an A:G mismatch and (ii) BGT in a ternary complex with UDP and an oligonucleotide containing a single central G:C base pair. The binary structure reveals a specific complex with the flipped-out, mismatched adenine exposed to the active site. Unexpectedly, the other structure shows the non-productive binding of an intermediate flipped-out base. Our structural analysis provides clear evidence for a passive process. |
==About this Structure== | ==About this Structure== | ||
| - | 1SXQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] with UDP as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/DNA_beta-glucosyltransferase DNA beta-glucosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.27 2.4.1.27] Full crystallographic information is available from [http:// | + | 1SXQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] with <scene name='pdbligand=UDP:'>UDP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/DNA_beta-glucosyltransferase DNA beta-glucosyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.27 2.4.1.27] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SXQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: flipped-out base]] | [[Category: flipped-out base]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:06:43 2008'' |
Revision as of 13:06, 21 February 2008
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BGT in complex with a 13mer DNA containing a central C:G base pair and UDP
Overview
Beta-glucosyltransferase (BGT) is a DNA-modifying enzyme and a glycosyltransferase. This inverting enzyme transfers glucose from UDP-glucose to the 5-hydroxymethyl cytosine bases of T4 phage DNA. From previous structural analyses we showed that Asp-100 and Asn-70 were, respectively, the catalytic base and the key residue for specific DNA recognition (Lariviere, L., Gueguen-Chaignon, V., and Morera, S. (2003) J. Mol. Biol. 330, 1077-1086). Here, we supply biochemical evidence supporting their essential roles in catalysis. We have also shown previously that BGT uses a base-flipping mechanism to access 5-hydroxymethyl cytosine (Lariviere, L., and Morera, S. (2002) J. Mol. Biol. 324, 483-490). Whether it is an active or a passive process remains unclear, as is the case for all DNA cleaving and modifying enzymes. Here, we report two crystal structures: (i) BGT in complex with a 13-mer DNA containing an A:G mismatch and (ii) BGT in a ternary complex with UDP and an oligonucleotide containing a single central G:C base pair. The binary structure reveals a specific complex with the flipped-out, mismatched adenine exposed to the active site. Unexpectedly, the other structure shows the non-productive binding of an intermediate flipped-out base. Our structural analysis provides clear evidence for a passive process.
About this Structure
1SXQ is a Single protein structure of sequence from Bacteriophage t4 with as ligand. Active as DNA beta-glucosyltransferase, with EC number 2.4.1.27 Full crystallographic information is available from OCA.
Reference
Structural evidence of a passive base-flipping mechanism for beta-glucosyltransferase., Lariviere L, Morera S, J Biol Chem. 2004 Aug 13;279(33):34715-20. Epub 2004 Jun 3. PMID:15178685
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