1zk7
From Proteopedia
(New page: 200px<br /><applet load="1zk7" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zk7, resolution 1.60Å" /> '''Crystal Structure of...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1zk7.gif|left|200px]]<br /><applet load="1zk7" size=" | + | [[Image:1zk7.gif|left|200px]]<br /><applet load="1zk7" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1zk7, resolution 1.60Å" /> | caption="1zk7, resolution 1.60Å" /> | ||
'''Crystal Structure of Tn501 MerA'''<br /> | '''Crystal Structure of Tn501 MerA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The ligand binding and catalytic properties of heavy metal ions have led | + | The ligand binding and catalytic properties of heavy metal ions have led to the evolution of metal ion-specific pathways for control of their intracellular trafficking and/or elimination. Small MW proteins/domains containing a GMTCXXC metal binding motif in a betaalphabetabetaalphabeta fold are common among proteins controlling the mobility of soft metal ions such as Cu(1+), Zn(2+), and Hg(2+), and the functions of several have been established. In bacterial mercuric ion reductases (MerA), which catalyze reduction of Hg(2+) to Hg(0) as a means of detoxification, one or two repeats of sequences with this fold are highly conserved as N-terminal domains (NmerA) of uncertain function. To simplify functional analysis of NmerA, we cloned and expressed the domain and catalytic core of Tn501 MerA as separate proteins. In this paper, we show Tn501 NmerA to be a stable, soluble protein that binds 1 Hg(2+)/domain and delivers it to the catalytic core at kinetically competent rates. Comparison of steady-state data for full-length versus catalytic core MerA using Hg(glutathione)(2) or Hg(thioredoxin) as substrate demonstrates that the NmerA domain does participate in acquisition and delivery of Hg(2+) to the catalytic core during the reduction catalyzed by full-length MerA, particularly when Hg(2+) is bound to a protein. Finally, comparison of growth curves for glutathione-depleted Escherichia coli expressing either catalytic core, full-length, or a combination of core plus NmerA shows an increased protection of cells against Hg(2+) in the media when NmerA is present, providing the first evidence of a functional role for this highly conserved domain. |
==About this Structure== | ==About this Structure== | ||
| - | 1ZK7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with SO4, FAD and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Mercury(II)_reductase Mercury(II) reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.16.1.1 1.16.1.1] Full crystallographic information is available from [http:// | + | 1ZK7 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=FAD:'>FAD</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Mercury(II)_reductase Mercury(II) reductase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.16.1.1 1.16.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZK7 OCA]. |
==Reference== | ==Reference== | ||
| Line 18: | Line 18: | ||
[[Category: Fiedler, D.]] | [[Category: Fiedler, D.]] | ||
[[Category: Ledwidge, R.]] | [[Category: Ledwidge, R.]] | ||
| - | [[Category: Miller, S | + | [[Category: Miller, S M.]] |
| - | [[Category: Pai, E | + | [[Category: Pai, E F.]] |
[[Category: Patel, B.]] | [[Category: Patel, B.]] | ||
| - | [[Category: Summers, A | + | [[Category: Summers, A O.]] |
[[Category: Zelikova, J.]] | [[Category: Zelikova, J.]] | ||
[[Category: FAD]] | [[Category: FAD]] | ||
| Line 28: | Line 28: | ||
[[Category: mercuric ion reductase]] | [[Category: mercuric ion reductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:16:22 2008'' |
Revision as of 14:16, 21 February 2008
|
Crystal Structure of Tn501 MerA
Overview
The ligand binding and catalytic properties of heavy metal ions have led to the evolution of metal ion-specific pathways for control of their intracellular trafficking and/or elimination. Small MW proteins/domains containing a GMTCXXC metal binding motif in a betaalphabetabetaalphabeta fold are common among proteins controlling the mobility of soft metal ions such as Cu(1+), Zn(2+), and Hg(2+), and the functions of several have been established. In bacterial mercuric ion reductases (MerA), which catalyze reduction of Hg(2+) to Hg(0) as a means of detoxification, one or two repeats of sequences with this fold are highly conserved as N-terminal domains (NmerA) of uncertain function. To simplify functional analysis of NmerA, we cloned and expressed the domain and catalytic core of Tn501 MerA as separate proteins. In this paper, we show Tn501 NmerA to be a stable, soluble protein that binds 1 Hg(2+)/domain and delivers it to the catalytic core at kinetically competent rates. Comparison of steady-state data for full-length versus catalytic core MerA using Hg(glutathione)(2) or Hg(thioredoxin) as substrate demonstrates that the NmerA domain does participate in acquisition and delivery of Hg(2+) to the catalytic core during the reduction catalyzed by full-length MerA, particularly when Hg(2+) is bound to a protein. Finally, comparison of growth curves for glutathione-depleted Escherichia coli expressing either catalytic core, full-length, or a combination of core plus NmerA shows an increased protection of cells against Hg(2+) in the media when NmerA is present, providing the first evidence of a functional role for this highly conserved domain.
About this Structure
1ZK7 is a Single protein structure of sequence from Pseudomonas aeruginosa with , and as ligands. Active as Mercury(II) reductase, with EC number 1.16.1.1 Full crystallographic information is available from OCA.
Reference
NmerA, the metal binding domain of mercuric ion reductase, removes Hg2+ from proteins, delivers it to the catalytic core, and protects cells under glutathione-depleted conditions., Ledwidge R, Patel B, Dong A, Fiedler D, Falkowski M, Zelikova J, Summers AO, Pai EF, Miller SM, Biochemistry. 2005 Aug 30;44(34):11402-16. PMID:16114877
Page seeded by OCA on Thu Feb 21 16:16:22 2008
