2fqw
From Proteopedia
(New page: 200px<br /><applet load="2fqw" size="450" color="white" frame="true" align="right" spinBox="true" caption="2fqw, resolution 1.71Å" /> '''PnrA from Treponema ...) |
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| - | [[Image:2fqw.gif|left|200px]]<br /><applet load="2fqw" size=" | + | [[Image:2fqw.gif|left|200px]]<br /><applet load="2fqw" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2fqw, resolution 1.71Å" /> | caption="2fqw, resolution 1.71Å" /> | ||
'''PnrA from Treponema pallidum as purified from E. coli (bound to inosine)'''<br /> | '''PnrA from Treponema pallidum as purified from E. coli (bound to inosine)'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Treponema pallidum, the bacterial agent of syphilis, cannot be cultivated | + | Treponema pallidum, the bacterial agent of syphilis, cannot be cultivated in vitro. This constraint has severely impeded the study of the membrane biology of this complex human pathogen. A structure-to-function approach thus was adopted as a means of discerning the likely function of Tp0319, a 35-kDa cytoplasmic membrane-associated lipoprotein of T. pallidum formerly designated as TmpC. A 1.7-A crystal structure showed that recombinant Tp0319 (rTp0319) consists of two alpha/beta domains, linked by three crossovers, with a deep cleft between them akin to ATP-binding cassette (ABC) receptors. In the cleft, a molecule of inosine was bound. Isothermal titration calorimetry demonstrated that rTp0319 specifically binds purine nucleosides (dissociation constant (Kd) approximately 10(-7) M). This predilection for purine nucleosides by rTp0319 is consistent with its likely role as a receptor component of a cytoplasmic membrane-associated transporter system. Reverse transcription-PCR analysis of RNA isolated from rabbit tissue-extracted T. pallidum additionally showed that tp0319 is transcriptionally linked to four other downstream open reading frames, thereby supporting the existence of an ABC-like operon (tp0319-0323). We herein thus re-name tp0319 as purine nucleoside receptor A (pnrA), with its operonic partners tp0320-0323 designated as pnrB-E, respectively. Our study not only infers that PnrA transports purine nucleosides essential for the survival of T. pallidum within its obligate human host, but to our knowledge, this is the first description of an ABC-type nucleoside transport system in any bacterium. PnrA has been grouped with a functionally uncharacterized protein family (HBG016869), thereby implying that other members of the family may have similar nucleoside-binding function(s). |
==About this Structure== | ==About this Structure== | ||
| - | 2FQW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Treponema_pallidum Treponema pallidum] with NOS as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 2FQW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Treponema_pallidum Treponema pallidum] with <scene name='pdbligand=NOS:'>NOS</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FQW OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Treponema pallidum]] | [[Category: Treponema pallidum]] | ||
| - | [[Category: Brautigam, C | + | [[Category: Brautigam, C A.]] |
| - | [[Category: Deka, R | + | [[Category: Deka, R K.]] |
[[Category: Machius, M.]] | [[Category: Machius, M.]] | ||
| - | [[Category: Norgard, M | + | [[Category: Norgard, M V.]] |
| - | [[Category: Tomchick, D | + | [[Category: Tomchick, D R.]] |
[[Category: NOS]] | [[Category: NOS]] | ||
[[Category: abc transport system]] | [[Category: abc transport system]] | ||
| Line 23: | Line 23: | ||
[[Category: ligand-binding protein]] | [[Category: ligand-binding protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:24:13 2008'' |
Revision as of 15:24, 21 February 2008
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PnrA from Treponema pallidum as purified from E. coli (bound to inosine)
Overview
Treponema pallidum, the bacterial agent of syphilis, cannot be cultivated in vitro. This constraint has severely impeded the study of the membrane biology of this complex human pathogen. A structure-to-function approach thus was adopted as a means of discerning the likely function of Tp0319, a 35-kDa cytoplasmic membrane-associated lipoprotein of T. pallidum formerly designated as TmpC. A 1.7-A crystal structure showed that recombinant Tp0319 (rTp0319) consists of two alpha/beta domains, linked by three crossovers, with a deep cleft between them akin to ATP-binding cassette (ABC) receptors. In the cleft, a molecule of inosine was bound. Isothermal titration calorimetry demonstrated that rTp0319 specifically binds purine nucleosides (dissociation constant (Kd) approximately 10(-7) M). This predilection for purine nucleosides by rTp0319 is consistent with its likely role as a receptor component of a cytoplasmic membrane-associated transporter system. Reverse transcription-PCR analysis of RNA isolated from rabbit tissue-extracted T. pallidum additionally showed that tp0319 is transcriptionally linked to four other downstream open reading frames, thereby supporting the existence of an ABC-like operon (tp0319-0323). We herein thus re-name tp0319 as purine nucleoside receptor A (pnrA), with its operonic partners tp0320-0323 designated as pnrB-E, respectively. Our study not only infers that PnrA transports purine nucleosides essential for the survival of T. pallidum within its obligate human host, but to our knowledge, this is the first description of an ABC-type nucleoside transport system in any bacterium. PnrA has been grouped with a functionally uncharacterized protein family (HBG016869), thereby implying that other members of the family may have similar nucleoside-binding function(s).
About this Structure
2FQW is a Single protein structure of sequence from Treponema pallidum with as ligand. Full crystallographic information is available from OCA.
Reference
The PnrA (Tp0319; TmpC) lipoprotein represents a new family of bacterial purine nucleoside receptor encoded within an ATP-binding cassette (ABC)-like operon in Treponema pallidum., Deka RK, Brautigam CA, Yang XF, Blevins JS, Machius M, Tomchick DR, Norgard MV, J Biol Chem. 2006 Mar 24;281(12):8072-81. Epub 2006 Jan 16. PMID:16418175
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