|
|
| Line 1: |
Line 1: |
| {{Orphan|date=June 2013}}
| | Traveler and entered one of many following phrase"s in the search bar, httpwww.google.com, <br><br>httpgroups.yahoo.com, httpyahoo.com, or maybe wwwgmail.com, hit search, "--" <br><br>Eh, Nothing, WHY? <br><br>So you have been aware of Google or Yahoo, thrilled the trusty Ie and wrote one of the following phrase"s in the search bar, httpwww.google.com, httpgroups.yahoo.com, httpyahoo.com, or maybe wwwgmail.com, hit search, "--" Eh, Nothing, WHY? <br><br>You"re not alone, over 3,000,000 people a year type in httpwww.google.com, over 2,000,000 type in httpgroups.yahoo.com, and 2,600,000 enter wwwgmail.com, all using the same result, Nix. The issue is two-fold, the clear answer is easy. Be taught extra information on a related article - Browse this webpage: [http://www.youtube.com/channel/UC9O6ujkCNDXZ-0U2D4qqf2A http://www.youtube.com/channel/uc9o6ujkcndxz-0u2d4qqf2a]. <br><br>Let us take a glance at one term particularly and you can apply the same treatment for others. You"ll likely have entered this in to a white text box anywhere in the top third section of your browser which may automatically have an AOL or MSN webpage showing, when you keyed in httpwww.google.com. This is actually a search text box where you have to key in what you"re searching for as a word or phrase. Using httpwww.google.com as an example, if you had keyed in only Google you"d have found the search engine finding its way back with an array of pages that have the word Google on their pages and then you might have selected what interests you. The search text box is where you key in, as an example, an expression like "acne and acupuncture." Hit the search key and bingo, several relevant internet sites will soon be found. <br><br>Httpwww.google.com isn"t a search term but an internet address. In the event you claim to learn further on [https://twitter.com/LeonkaTw the link], there are tons of libraries people might investigate. If you have the correct address and desire to visit that site, you need to enter it in the address bar which will be usually only under the top toolbar of one"s browser. You will see that many handle bars try it out button on the right in place of a search button as-in the search field described before. <br><br>The final part of the solution is in the spelling of httpwww.google.com. Discover extra info on [http://www.geni.com/people/Leon-Puhachevsky/299985687440008031 leon puhachevsky] by browsing our poetic use with. Httpwww.google.com should actually be written the following, http://www.google.com/.. You had been mighty near, but computers are wickedly sensible and an absent forward cut usually means despair. <br><br>In conclusion; <br><br>1- Search phrases go in-the search text box, <br><br>2- Addresses get in-the top handle club, <br><br>3- Addresses have to be spelt precisely. <br><br>Httpwww.google.com adjusted is http://www.google.com/, <br><br>Httpgroups.yahoo.com fixed is http://groups.yahoo.com/, <br><br>Httpyahoo.com corrected is http://www.yahoo.com/, <br><br>Wwwgmail.com adjusted is http://www.gmail.com/. <br><br>Happy exploring!.Leon Puhachevsky<br><br>If you liked this post and you would certainly such as to obtain more information concerning behavioral health - [http://www.purevolume.com/listeners/ossifieddonor5075 purevolume.com] - kindly visit our own webpage. |
| | |
| {{Infobox protein family
| |
| | Symbol = FeThRed_A
| |
| | Name = Ferredoxin thioredoxin reductase variable alpha chain
| |
| | image = PDB 1dj7 EBI.jpg
| |
| | width =
| |
| | caption = crystal structure of ferredoxin thioredoxin reductase
| |
| | Pfam = PF02941
| |
| | Pfam_clan =
| |
| | InterPro = IPR004207
| |
| | SMART =
| |
| | PROSITE =
| |
| | MEROPS =
| |
| | SCOP = 1dj7
| |
| | TCDB =
| |
| | OPM family =
| |
| | OPM protein =
| |
| | CAZy =
| |
| | CDD =
| |
| }}
| |
| {{Infobox protein family
| |
| | Symbol = FeThRed_B
| |
| | Name = Ferredoxin thioredoxin reductase catalytic beta chain
| |
| | image = PDB 1dj7 EBI.jpg
| |
| | width =
| |
| | caption = crystal structure of ferredoxin thioredoxin reductase
| |
| | Pfam = PF02943
| |
| | Pfam_clan =
| |
| | InterPro = IPR004209
| |
| | SMART =
| |
| | PROSITE =
| |
| | MEROPS =
| |
| | SCOP = 1dj7
| |
| | TCDB =
| |
| | OPM family =
| |
| | OPM protein =
| |
| | CAZy =
| |
| | CDD =
| |
| }}
| |
| | |
| '''Ferredoxin-thioredoxin reductase''' {{EC number|1.8.7.2}}, systematic name ''ferredoxin:thioredoxin disulfide oxidoreductase,'' is a [4Fe-4S] [[protein]] that plays an important role in the [[ferredoxin]]/[[thioredoxin]] regulatory chain. It catalyzes the following reaction:
| |
| | |
| ::: 2 reduced [[ferredoxin]] + [[thioredoxin]] [[disulfide]] <math>\rightleftharpoons</math> 2 oxidized ferredoxin + thioredoxin [[thiols]] + 2 H<sup>+</sup>
| |
| | |
| Ferredoxin-Thioredoxin reductase (FTR) converts an [[electron]] signal (photoreduced ferredoxin) to a [[thiol]] signal (reduced thioredoxin), regulating [[enzyme]]s by [[Redox|reduction]] of specific [[disulfide]] groups. It [[catalysis|catalyses]] the light-dependent activation of several [[photosynthesis]] [[enzymes]] and constitutes the first historical example of a thiol/disulfide exchange cascade for enzyme regulation.<ref name="pmid16245124">{{cite journal | author = Buchanan B, Schurmann P, Wolosiuk R, Jacquot J | title = The ferredoxin/thioredoxin system: from discovery to molecular structures and beyond | journal = Discoveries in Photosynthesis | volume = 73 | pages = 215–222 | year = 2002 | pmid = 16245124| url = | doi=10.1023/A:1020407432008 | issue=1-3}}</ref> It is a [[heterodimer]] of subunit alpha and subunit beta. Subunit alpha is the variable subunit, and beta is the [[catalytic]] chain. The [[secondary structure|structure]] of the beta subunit has been determined and found to fold around the [[FeS]] cluster.<ref name="pmid10649999">{{cite journal | author = Dai S, Schwendtmayer C, Schurmann P, Ramaswamy S, Eklund H | title = Redox signaling in chloroplasts: cleavage of disulfides by an iron-sulfur cluster | journal = Science | volume = 287 | issue = 5453 | pages = 655–8 |date=January 2000 | pmid = 10649999 | doi = 10.1126/science.287.5453.655| url = }}</ref>
| |
| | |
| ==Biological Function==
| |
| Major groups of oxygen-producing, [[photosynthesis|photosynthetic]] organisms such as [[cyanobacteria]], [[algae]], [[C4 carbon fixation#C4pathway|C4]], [[C3 carbon fixation|C3]], and [[crassulacean acid metabolism]] (CAM) plants use Ferredoxin-thioredoxin reductase for [[carbon fixation]] regulation.<ref name= "Hirasawa">Hirasawa, Masakazu, Peter Schurmann, and Jean-Pierre Jacquot. "Oxidation-Reduction Properties of Chloroplast Thioredoxins, Ferredoxin:Thioredoxin Reductase, and Thioredoxin f-Regulated Enzymes." ''Biochemistry'' 38 (1999): 5200-5205.</ref> FTR, as part of a greater Ferredoxin-Thioredoxin system, allows plants to change their metabolism based on light intensity. Specifically, the Ferredoxin-Thioredoxin system controls enzymes in the [[Calvin Cycle]] and [[Pentose phosphate pathway]] - allowing plants to balance carbohydrate synthesis and degradation based on the availability of light.<ref name="Buchanan">{{cite journal | author = Buchanan | title = Regulation of CO2 assimilation in oxygenic photosynthesis: The ferredoxin/thioredoxin system: Perspective on its discovery, present status, and future development | journal = Archives of Biochemistry and Biophysics | volume = 288 | issue = 1 | pages = 1–9 |date=July 1991 | pmid = 1910303 | doi = 10.1016/0003-9861(91)90157-E| url = }}</ref> In the light, photosynthesis harnesses light energy and [[Reduction|reduces]] [[Ferredoxin]]. Using FTR, reduced Ferredoxin then reduces [[Thioredoxin]]. Thioredoxin, through [[Disulfide bond#Preparation and reactions|thiol/disulfide exchange]], then activates carbohydrate synthesis enzymes such as chloroplast [[fructose-1,6-bisphosphatase]], [[Sedoheptulose-bisphosphatase]], and [[phosphoribulokinase]].<ref name="Jacquot">{{cite journal | author = Jacquot J, Lancelin J, Meyer Y | title = Thioredoxins: structure and function in plant cells | journal = New Phytologist | volume = 136 | issue = 4 | pages = 543–570 |date=August 1997 | jstor = 2559149 | url = }}</ref> As a result, light uses FTR to activate carbohydrate biosynthesis. In the dark, Ferredoxin remains oxidized. This leaves Thioredoxin inactive and allows carbohydrate breakdown to dominate metabolism.<ref name="Buchanan"/>
| |
| | |
| ==Structure==
| |
| Ferredoxin-Thioredoxin Reductase is an α-β [[protein dimer|heterodimer]] of approximately 30 kDa.<ref name="Staples">{{cite journal | author = Staples C, Ameyibor E, Fu W, Gardet-Salvi L, Stritt-Etter A, Schurmann P, Knaff D, Johnson M | title = The Function and Properties of the Iron-sulfur Center in Spinach Ferredoxin:Thioredoxin Reductase: A New Biological Role for Iron-Sulfur Clusters | journal = Biochemistry | volume = 35 | pages = 11425–11434 |date=September 1996 | doi = 10.1021/bi961007p| url = | pmid=8784198}}</ref> FTR structure across different plant species include a conserved catalytic β subunit and a variable α subunit. The structure of FTR from ''[[Synechocystis]]'' sp. PCC6803 has been studied in detail and resolved at 1.6 Å.<ref name="pmid10649999"/> FTR resembles a thin [[concave]] disc, 10 Å across the center where a [[Iron-sulfur cluster|[4Fe-4S cluster]]] resides. One side of the cluster center contains redox-active disulfide bonds that reduce Thioredoxin while the opposite docks with reduced Ferredoxin. This two sided disc structure allows FTR to simultaneously interact with Thioredoxin and Ferredoxin.<ref name="pmid10649999"/>
| |
| | |
| [[File:Ferredoxin-Thioredoxin Reductase Fe-S center with surrounding Cysteine residues.jpg|thumbnail|[4Fe-4S] cluster in the Ferredoxin-thioredoxin reductase catalytic β subunit is surrounded by several Cysteine residues.]] | |
| | |
| The variable α subunit has an open [[Beta-barrel|β barrel]] structure made of five [[antiparallel (biochemistry)#Beta sheet|antiparallel β strands]]. Its interaction with the catalytic subunit occurs mainly with two loops between β strands. The residues in these two loops are mostly conserved and are thought to stabilize the 4Fe-4S cluster in the catalytic subunit. Structurally, the α subunit is very similar to the PsaE protein, a subunit of [[Photosystem I]], though the similarity is not seen in their sequences or functions.<ref name="pmid10649999"/>
| |
| | |
| The catalytic β subunit has a general α-helical structure with an [[Iron-sulfur cluster|[4Fe-4S center]]]. The FeS center and redox-active [[Cysteine]] residues are located within the loops of these helices. Cysteine-55, 74, 76, and 85 are coordinated in cubane-like geometry around the Fe-S center.<ref name="pmid10649999"/>
| |
| | |
| ==Enzymatic Mechanism==
| |
| FTR is ''unique'' among [[thioredoxin reductase]]s because it uses an Fe-S cluster [[cofactor (biochemistry)|cofactor]] rather than [[flavoprotein]]s to reduce disulfide bonds. FTR catalysis begins with its interaction with reduced Ferredoxin. This proceeds with the attraction between FTR Lys-47 and Ferredoxin Glu-92.<ref name="Dai">{{cite journal | author = Dai S, Friemann R, Glauser D, Bourqin F, Manieri W, Schurmann P, Eklund H | title = Structural snapshots along the reaction pathway of ferredoxin-thioredoxin reductase | journal = Nature | volume = 448 | pages = 92–96 |date=July 2007 | pmid = 17611542 | url = | doi=10.1038/nature05937 | issue=7149}}</ref> One electron from Ferredoxin and one electron from the Fe-S center is abstracted to break FTR's Cys-87 and Cys-57 disulfide bond, create a nucleophilic Cys-57, and oxidize the Fe-S center from [4Fe-4S]<sup>2+</sup> to [4Fe-4S]<sup>3+</sup>.<ref name="Jameson">{{cite journal | author = Jameson G, Elizabeth W, Manieri W, Schurmann P, Johnson M, Huynh B | title = Spectroscopic Evidence for Site Specific Chemistry at a Unique Iron Site of the [4Fe-4S] Cluster in Ferredoxin:Thioredoxin Reductase | journal = Journal of American Chemical Society | volume = 25 | pages = 1146–1147 | year = 2003 | pmid = 12553798 | doi = 10.1021/ja029338e| url = }}</ref> The structure of this one-electron (from Ferredoxin) intermediate is contested: Staples et al. suggest Cys-87 is coordinated to a Sulfur in the Fe-S center<ref name="Staples"/> while Dai et al. argue Cys-87 is coordinated to an Iron.<ref name="pmid10649999"/> Next, the nucleophilic Cys-57, encouraged by an adjacent [[Histidine]] residue,<ref name="Glauser">{{cite journal | author = Glauser DA, Bourquin F, Manieri W, Schurmann P | title = Characterization of ferredoxin:thioredoxin reductase modified by site-directed mutagenesis | journal = The Journal of Biological Chemistry | volume = 279 | issue = 16 | pages = 16662–16669 |date=April 2004 | pmid = 14769790 | url = | doi=10.1074/jbc.M313851200}}</ref> attacks a disulfide bridge on Thioredoxin, creating a hetero-disulfide Thioredoxin intermediate. Lastly, a newly docked Ferredoxin molecule delivers the final electron to the FeS center, reducing it to its original 2+ state, reforming the Cys-87, Cys-57 disulfide, and fully reducing thioredoxin to two [[thiol]]s.<ref name="Dai"/>
| |
| | |
| ==References==
| |
| {{reflist}}
| |
| {{InterPro content|IPR004209}}
| |
| | |
| {{InterPro content|IPR004207}}
| |
| | |
| [[Category:Protein domains]]
| |
Traveler and entered one of many following phrase"s in the search bar, httpwww.google.com,
httpgroups.yahoo.com, httpyahoo.com, or maybe wwwgmail.com, hit search, "--"
Eh, Nothing, WHY?
So you have been aware of Google or Yahoo, thrilled the trusty Ie and wrote one of the following phrase"s in the search bar, httpwww.google.com, httpgroups.yahoo.com, httpyahoo.com, or maybe wwwgmail.com, hit search, "--" Eh, Nothing, WHY?
You"re not alone, over 3,000,000 people a year type in httpwww.google.com, over 2,000,000 type in httpgroups.yahoo.com, and 2,600,000 enter wwwgmail.com, all using the same result, Nix. The issue is two-fold, the clear answer is easy. Be taught extra information on a related article - Browse this webpage: http://www.youtube.com/channel/uc9o6ujkcndxz-0u2d4qqf2a.
Let us take a glance at one term particularly and you can apply the same treatment for others. You"ll likely have entered this in to a white text box anywhere in the top third section of your browser which may automatically have an AOL or MSN webpage showing, when you keyed in httpwww.google.com. This is actually a search text box where you have to key in what you"re searching for as a word or phrase. Using httpwww.google.com as an example, if you had keyed in only Google you"d have found the search engine finding its way back with an array of pages that have the word Google on their pages and then you might have selected what interests you. The search text box is where you key in, as an example, an expression like "acne and acupuncture." Hit the search key and bingo, several relevant internet sites will soon be found.
Httpwww.google.com isn"t a search term but an internet address. In the event you claim to learn further on the link, there are tons of libraries people might investigate. If you have the correct address and desire to visit that site, you need to enter it in the address bar which will be usually only under the top toolbar of one"s browser. You will see that many handle bars try it out button on the right in place of a search button as-in the search field described before.
The final part of the solution is in the spelling of httpwww.google.com. Discover extra info on leon puhachevsky by browsing our poetic use with. Httpwww.google.com should actually be written the following, http://www.google.com/.. You had been mighty near, but computers are wickedly sensible and an absent forward cut usually means despair.
In conclusion;
1- Search phrases go in-the search text box,
2- Addresses get in-the top handle club,
3- Addresses have to be spelt precisely.
Httpwww.google.com adjusted is http://www.google.com/,
Httpgroups.yahoo.com fixed is http://groups.yahoo.com/,
Httpyahoo.com corrected is http://www.yahoo.com/,
Wwwgmail.com adjusted is http://www.gmail.com/.
Happy exploring!.Leon Puhachevsky
If you liked this post and you would certainly such as to obtain more information concerning behavioral health - purevolume.com - kindly visit our own webpage.