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32-638: [REDACTED] Look up fis in Wiktionary, the free dictionary. FIS or fis may refer to: Science and technology [ edit ] Fis , an E. Coli gene Fis phenomenon , a phenomenon in linguistics F♯ (musical note) Flight information service , an air traffic control service Frame Information Structure , a Serial ATA technology Organizations [ edit ] FIS (company) , an American financial services company Fairy Investigation Society Federal Intelligence Service ,

64-754: A Swiss intelligence service Festival Internacional de Santander , a Spanish music festival Fiji Intelligence Services Fish Information and Services , an international news agency Flandreau Indian School Foreign Intelligence Service (Russia) (Russian: Служба внешней разведки Российской Федерации , romanized : Sluzhba vneshney razvedki Rossiyskoy Federatsii , IPA: [ˈsluʐbə ˈvnʲɛʂnʲɪj rɐˈzvʲɛtkʲɪ] ) Frankfurt International School French International School of Hong Kong Fukuoka International School International Ski and Snowboard Federation (French: Fédération Internationale de Ski et de Snowboard ) Islamic Salvation Front (French: Front Islamique du Salut ),

96-491: A defunct political party in Algeria Italian Fencing Federation (Italian: Federazione Italiana Scherma ) and Italian Scout Federation (Italian: Federazione Italiana dello Scautismo ) Surname [ edit ] Julio Fis (born 1974), Spanish handball player Ljubomir Pavićević Fis (born 1927), Serbian designer Anthropology [ edit ] Fis is also

128-460: A native turn region signals the folding cascade to start, where a native turn is one that is present in the final folded structure. In the folding of overall proteins, the turn may originate not in the native turn region but in the C-strand of the beta-hairpin. This turn then propagates through the C-strand (the beta strand leading to C-terminus) until it reaches the native turn region. Sometimes

160-499: A nutritional upshift and is important in the physiological roles Fis plays in the cell. It is a global regulatory protein in Escherichia coli that activates ribosomal RNA ( rRNA ) transcription by binding to three upstream activation sites of the rRNA promoter and enhances transcription 5 to 10 fold in vivo . Fis overexpression results in different effects on cell growth depending on nutrient conditions. The Fis nucleoid protein

192-527: A proline leading up to the native turn region) and less conformational options. The initial turn formation takes place in about 1 μs. Once the initial turn has been established, two mechanisms have been proposed as to how the rest of the beta-hairpin folds: a hydrophobic collapse with side-chain level rearrangements, or the more accepted zipper-like mechanism. The β-hairpin loop motif can be found in many macromolecular proteins. However, small and simple β-hairpins can exist on their own as well. To see this clearly,

224-413: A three-residue, and class 4 with a four-residue. Class 5 does not exist as that primary hairpin is already defined in class 1. Pi This classification scheme not only accounts for various degrees of hydrogen bonding, but also says something about the biological behavior of the hairpin. Single amino acid replacements may destroy a particular hydrogen bond, but will not unfold the hairpin or change its class. On

256-478: A transcriptional repressor of ''mom'' promoter . There is data that shows Fis mediates its repressive effect by denying access to RNA polymerase at the mom promoter. combined A repressive effect of Fis and previously characterized negative regulatory factors could be responsible to keep the gene silenced most of the time. In addition to bringing about overall downregulation of the Mu genome , it also ensures silencing of

288-639: Is adjacent to the C-terminus of the next), and linked by a short loop of two to five amino acids . Beta hairpins can occur in isolation or as part of a series of hydrogen bonded strands that collectively comprise a beta sheet . Researchers such as Francisco Blanco et al. have used protein NMR to show that beta-hairpins can be formed from isolated short peptides in aqueous solution, suggesting that hairpins could form nucleation sites for protein folding . Beta hairpins were originally categorized solely by

320-477: Is cotranscribed with the upstream dusB gene encoding a tRNA-modifying enzyme. DusB protein levels are very low even under conditions when there is high transcription of the operon and high levels of Fis protein. Fis has been deemed a bacterial chromatin architectural protein. Besides modulating chromatin architecture, it is known to influence numerous promoters of E. coli and several other bacteria. Both in vivo and in vitro studies indicate that Fis acts as

352-819: Is different from Wikidata All article disambiguation pages All disambiguation pages Fis Fis was first discovered for its role in stimulating Gin catalyzed inversion of the G segment of phage Mu genome. Fis was originally identified as the f actor for i nversion s timulation of the homologous Hin and Gin site-specific DNA recombinases of Salmonella and phage Mu, respectively. This small, basic, DNA-bending protein has recently been shown to function in many other reactions including phage lambda site-specific recombination, transcriptional activation of rRNA and tRNA operons, repression of its own synthesis, and oriC-directed DNA replication. Cellular concentrations of Fis vary tremendously under different growth conditions which may have important regulatory implications for

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384-546: Is differentiated by its fast increase in synthesis rates following nutrient upshifts and its abundance in rapidly growing E. coli cells. Fis has been known to activate ribosomal RNA transcription, as well other genes. It has a direct role in upstream activation of rRNA promoters. Fis binds to a recombinational enhancer sequence that is required to stimulate hin -mediated DNA inversion. It has also been shown to prevent initiation of DNA replication from oriC . It has been shown that sequences from 32 to 94 nucleotides upstream of

416-426: Is important in the adaptation of P. putida during colonization of plant roots by promoting biofilm formation when the migration of bacteria is no longer advantageous. It was demonstrated that Fis is essential for the stability of the linear plasmid pDSIUDi and affects the motility of S. Typhi . Fis buffers decrease of negative supercoiling in tyrT and rrnA expression. The upstream FIS binding site of rrnA

448-407: Is largely shut off, and intracellular Fis levels decrease as a function of cell division. Fis synthesis also transiently increases when exponentially growing cells are shifted to a richer medium. The magnitude of the peak of Fis synthesis appears to reflect the extent of the nutritional upshift. fis mRNA levels closely resemble the protein expression pattern, suggesting that regulation occurs largely at

480-580: Is required for this and it's probable that FIS enables local DNA curvature. See Travers and Muskhelishvili 2005 for more detail. Beta hairpin The beta hairpin (sometimes also called beta-ribbon or beta-beta unit ) is a simple protein structural motif involving two beta strands that look like a hairpin . The motif consists of two strands that are adjacent in primary structure , oriented in an antiparallel direction (the N-terminus of one sheet

512-581: The Pin1 Domain protein is shown to the left as an example. Proteins that are β-sheet rich, also called WW domains , function by adhering to proline-rich and/or phosphorylated peptides to mediate protein–protein interactions . The "WW" refers to two tryptophan (W) residues that are conserved within the sequence and aid in the folding of the β-sheets to produce a small hydrophobic core. These tryptophan residues can be seen below (right) in red. This enzyme binds its ligand through van der Waals forces of

544-473: The fis AUG are responsible for increasing fis lacZ translation reporter activities over 100 fold. Within this region, an AU sequence element centered 35 nucleotides upstream of the fis AUG increases fis translation by as much as 15 fold. Formation of a supposed RNA secondary structure element beginning 50 nucleotides upstream of the AUG also positively affects fis translation by up to 10 fold. The fis gene

576-479: The residue interactions leading up to the native turn region are too strong, causing reverse propagation. However, once the native turn does form, interactions between prolines and tryptophan residues (seen in image at right) in the region help to stabilize the turn, preventing "roll back" or dissolution. Researchers believe that turns do not originate in the N-strand, due to increased rigidity (often caused by

608-862: The Albanian word for the Albanian clans . See also [ edit ] FI (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title FIS . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=FIS&oldid=1236881527 " Categories : Disambiguation pages Disambiguation pages with surname-holder lists Hidden categories: Articles containing Russian-language text Pages with Russian IPA Articles containing French-language text Articles containing Italian-language text Short description

640-584: The advantageous but potentially lethal mom gene. Fis as a critical regulator of capsule expression. Fis is also involved in the regulation of a range of genes in bacterial species such as P. multocida , Enteroaggregative Escherichia coli, similar organisms. Some of these genes include important virulence factors. The role of fis is well studied in E. coli, but its role in pseudomonads has only been examined briefly. Recent studies in Enterobacteriaceae have shown that fis positively regulates

672-525: The bacterial chromosome structure and the initiation of DNA replication. It is a nucleoid-associated protein in Escherichia coli that is abundant during early exponential growth in rich medium but is in short supply during stationary phase. When stationary-phase cells are subcultured into a rich medium, Fis levels increase from less than 100 to over 50,000 copies per cell prior to the first cell division. As cells enter exponential growth, nascent synthesis

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704-410: The conserved tryptophans and the proline-rich areas of the ligand. Other amino acids can then associate with the hydrophobic core of the β-hairpin structure to enforce secure binding. It is also common to find proline residues within the actual loop portion of the β-hairpin, since this amino acid is rigid and contributes to the "turn" formation. These proline residues can be seen as red side chains in

736-472: The flagellar movement of bacteria. Observations in Pseudomonas putida demonstrate fis reduced the migration of P. putida onto the apices of barley roots and thereby the competitiveness of bacteria on the roots. It was also observed that the overexpression of fis drastically reducing swimming motility and facilitated the formation of P. putida biofilm. It is possible that the elevated expression of Fis

768-545: The image of the Pin1 WW domain below (left). The design of peptides that adopt β-hairpin structure (without relying on metal binding, unusual amino acids, or disulfide crosslinks) has made significant progress and yielded insights into protein dynamics. Unlike α-helices , β-hairpins are not stabilized by a regular hydrogen bonding pattern. As a result, early attempts required at least 20–30 amino acid residues to attain stable tertiary folds of β-hairpins. However, this lower limit

800-456: The loop sequence but also signal the end of the loop, thus defining this hairpin as a three-residue loop. This single hydrogen bond is then removed to create the tertiary hairpin; a five-residue loop with doubly bound residues. This pattern continues indefinitely and defines all beta hairpins within the class. Class 2 follows the same pattern beginning with a two-residue loop with terminating residues that share two hydrogen bonds. Class 3 begins with

832-434: The mechanism through which micro-domains fold can help to shed light onto the folding patterns of whole proteins . Studies of a beta hairpin called chignolin (see Chignolin on Proteopedia ) have uncovered a stepwise folding process that drives beta-hairpin folding. This hairpin has sequence features similar to over 13,000 known hairpins, and thus may serve as a more general model for beta hairpin formation. The formation of

864-458: The number of amino acid residues in their loop sequences, such that they were named one-residue, two-residue, etc. This system, however, is somewhat ambiguous as it does not take into account whether the residues that signal the end of the hairpin are singly or doubly hydrogen bonded to one another. An improved means of classification has since been proposed by Milner-White and Poet. Beta hairpins are broken into four distinct classes as depicted in

896-408: The other hand, amino acid insertions and deletions will have to unfold and reform the entire beta strand in order to avoid a beta bulge in the secondary structure. This will change the class of the hairpin in the process. As substitutions are the most common amino acid mutations, a protein could potentially undergo a conversion without affecting the functionality of the beta hairpin. Understanding

928-412: The physiological role of Fis in these different reactions. Structurally, Fis folds into four α-helices (A–D) and a β-hairpin . Helices A and B provide the contacts between Fis monomers, facilitating dimer formation, whereas the C and D helices form a helix-turn-helix motif that is essential for DNA binding. Fis is a very important small nucleotide-associated protein which plays a role in affecting

960-436: The publication's Figure 1. Each class begins with the smallest possible number of loop residues and progressively increases the loop size by removing hydrogen bonds in the beta sheet. The primary hairpin of class 1 is a one-residue loop where the bound residues share two hydrogen bonds. One hydrogen bond is then removed to create a three-residue loop, which is the secondary hairpin of class 1. Singly bound residues are counted in

992-525: The transcriptional level. Two RNA polymerase-binding sites and at least six high-affinity Fis-binding sites are present in the fis promoter region. Expression of this fis operon is negatively regulated by Fis in vivo and purified Fis can prevent stable complex formation by RNA polymerase at the fis promoter in vitro. However, autoregulation only partially accounts for the expression pattern of Fis. Fluctuations in Fis levels have been shown to serve as an early signal of

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1024-605: Was reduced to 12 amino acids by the stability gains conferred by the incorporation of tryptophan-tryptophan cross-strand pairs. Two nonhydrogen-bonding tryptophan pairs have been shown to interlock in a zipper-like motif, stabilizing the β-hairpin structure while still allowing it to remain water-soluble . The NMR structure of a tryptophan zipper (trpzip) β-peptide shows the stabilizing effect of favorable interactions between adjacent indole rings. The synthesis of trpzip β-hairpin peptides has incorporated photoswitches that facilitate precise control over folding. Several amino acids in

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