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71.
Reciprocal control of flowering time by OsSOC1 in transgenic Arabidopsis and by FLC in transgenic rice 总被引:1,自引:1,他引:1
Tadege M Sheldon CC Helliwell CA Upadhyaya NM Dennis ES Peacock WJ 《Plant biotechnology journal》2003,1(5):361-369
In a screen for MADS box genes which activate and/or repress flowering in rice, we identified a gene encoding a MADS domain protein (OsSOC1) related to the Arabidopsis gene AtSOC1. AtSOC1 and OsSOC1 show a 97% amino acid similarity in their MADS domain. The rice gene contains a large first intron of 27.6 kb compared to the 1 kb intron in Arabidopsis. OsSOC1 is located on top of the short arm of chromosome 3, tightly linked to the heading date locus, Hd9. OsSOC1 is expressed in vegetative tissues, and expression is elevated at the time of floral initiation, 40-50 days after sowing, and remains uniformly high thereafter, similar to the expression pattern of AtSOC1. The constitutive expression of OsSOC1 in Arabidopsis results in early flowering, suggesting that the rice gene is a functional equivalent of AtSOC1. We were not able to identify FLC-like sequences in the rice genome; however, we show that ectopic expression of the Arabidopsis FLC delays flowering in rice, and the up-regulation of OsSOC1 at the onset of flowering initiation is delayed in the AtFLC transgenic lines. The reciprocal recognition and flowering time effects of genes introduced into either Arabidopsis or rice suggest that some components of the flowering pathways may be shared. This points to a potential application in the manipulation of flowering time in cereals using well characterized Arabidopsis genes. 相似文献
72.
M NM Ollagnier-de-Choudens S Sanakis Y Abdel-Ghany SE Rousset C Ye H Fontecave M Pilon-Smits EA Pilon M 《The Journal of biological chemistry》2007,282(25):18254-18264
In this study we characterize two novel chloroplast SufE-like proteins from Arabidopsis thaliana. Other SufE-like proteins, including the previously described A. thaliana CpSufE, participate in sulfur mobilization for Fe-S biosynthesis through activation of cysteine desulfurization by NifS-like proteins. In addition to CpSufE, the Arabidopsis genome encodes two other proteins with SufE domains, SufE2 and SufE3. SufE2 has plastid targeting information. Purified recombinant SufE2 could activate the cysteine desulfurase activity of CpNifS 40-fold. SufE2 expression was flower-specific and high in pollen; we therefore hypothesize that SufE2 has a specific function in pollen Fe-S cluster biosynthesis. SufE3, also a plastid targeted protein, was expressed at low levels in all major plant organs. The mature SufE3 contains two domains, one SufE-like and one with similarity to the bacterial quinolinate synthase, NadA. Indeed SufE3 displayed both SufE activity (stimulating CpNifS cysteine desulfurase activity 70-fold) and quinolinate synthase activity. The full-length protein was shown to carry a highly oxygen-sensitive (4Fe-4S) cluster at its NadA domain, which could be reconstituted by its own SufE domain in the presence of CpNifS, cysteine and ferrous iron. Knock-out of SufE3 in Arabidopsis is embryolethal. We conclude that SufE3 is the NadA enzyme of A. thaliana, involved in a critical step during NAD biosynthesis. 相似文献
73.
Shankarappa KS Rangaswamy KT Aswatha Narayana DS Rekha AR Raghavendra N Lakshminarayana Reddy CN Chancellor TC Maruthi MN 《Bulletin of entomological research》2007,97(5):503-513
The aim of this study was to develop and optimize silverleaf bioassay, esterase analysis and PCR-based techniques to distinguish quickly and reliably biotype B of the whitefly, Bemisia tabaci (Gennadius), from Indian indigenous biotypes. Zucchini and squash readily develop silverleaf symptoms upon feeding by the B biotype, but they are not readily available in Indian markets. A local pumpkin variety 'Big' was, therefore, used in silverleaf assay, which developed symptoms similar to those on zucchini and squash and can be used reliably to detect B biotype. Analysis of non-specific esterases of B and the indigenous biotypes indicated both quantitative and qualitative differences in esterase patterns. Two high molecular weight bands were unique to B biotype and they occurred in abundance. These esterases were used to develop quick and field-based novel detection methods for differentiating B from the indigenous biotypes. Development of these simple and cost-effective protocols has wider application as they can be potentially used to identify other agricultural pests. Mitochondrial cytochrome oxidase I gene sequences and randomly amplified polymorphic DNA (RAPD) polymorphisms, generated using the primer OpB11, were also found useful for detecting B. tabaci biotypes. A B biotype-specific RAPD band of 800 bp was sequenced, which was used to a develop sequence characterized amplified region (SCAR) marker. The SCAR marker involved the development of B biotype-specific primers that amplified 550 bp PCR products only from B biotype genomic DNA. Silverleaf assay, esterases, RAPDs or a SCAR marker were used in combination to analyse whitefly samples collected from selected locations in India, and it was found that any of these techniques can be used singly or in combination to detect B biotype reliably. The B biotype was found in southern parts of India but not in the north in 2004-06. 相似文献
74.
Zameer Ahmed Manickam Gurusaran Prasanth Narayana Kala Sekar Dinesh Kumar Jayapal Mohanapriya Marthandan Kirti Vaishnavi Kanagaraj Sekar 《Bioinformation》2014,10(1):48-51
The primary structure of a protein molecule comprises a linear chain of amino acid residues. Certain parts of this linear chain are
unique in nature and function. They can be classified under different categories and their roles studied in detail. Two such unique
categories are the palindromic sequences and the Single Amino Acid Repeats (SAARs), which plays a major role in the structure,
function and evolution of the protein molecule. In spite of their presence in various protein sequences, palindromes have not yet
been investigated in detail. Thus, to enable a comprehensive understanding of these sequences, a computing engine, PPS, has been
developed. The users can search the occurrences of palindromes and SAARs in all the protein sequences available in various
databases and can view the three-dimensional structures (in case it is available in the known three-dimensional protein structures
deposited to the Protein Data Bank) using the graphics plug-in Jmol. The proposed server is the first of its kind and can be freely
accessed through the World Wide Web.
Availability
URL http://pranag.physics.iisc.ernet.in/pps/ 相似文献75.
R. Shylaja Devi Kalyan Kumar Thakasi H. S. Murali K. Prakash Narayana Reddy H. V. Batra 《Indian journal of microbiology》2012,52(3):449-455
Staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin-1 are the super antigens responsible for diseases such as staphylococcal food poisoning and toxic shock syndrome. At low serum concentrations, SEB can trigger toxic shock, profound hypotension and multi organ failure and hence is recognized as biowarfare molecule. In this study, a multidomain fusion protein (r-TE) was generated with specificity for SEB and toxic shock syndrome toxin (Tsst-1). The fusion gene comprising the conserved regions of seb and the tsst genes was codon-optimized for expression in Escherichia coli and encoded a 26 kDa recombinant multidomain chimeric protein (r-TE). Hyperimmune antiserum raised against r-TE specifically reacted with SEB (~28 kDa) and Tsst-1 (~22 kDa) components during Western blot analysis and by plate ELISA in confirmed toxin producing strains of S. aureus. The antigenicity of the SEB component of the r-TE protein was also confirmed using TECRA kit. The described procedure of creating a single protein molecule carrying components of two different toxins whilst still retaining the original antigenic determinants of individual toxins proved highly advantageous in the development of rapid, reliable and cost effective immunoassays and may also have the potential to serve as candidate molecule for vaccine studies. 相似文献
76.
Prasad NK Vindal V Narayana SL Ramakrishna V Kunal SP Srinivas M 《Journal of molecular modeling》2012,18(5):2013-2019
Laccases belong to multicopper oxidases, a widespread class of enzymes implicated in many oxidative functions in various industrial
oxidative processes like production of fine chemicals to bioremediation of contaminated soil and water. In order to understand
the mechanisms of substrate binding and interaction between substrates and Pycnoporus cinnabarinus laccase, a homology model was generated. The resulted model was further validated and used for docking studies with toxic
industrial dyes- acid blue 74, reactive black 5 and reactive blue 19. Interactions of chemical mediators with the laccase
was also examined. The docking analysis showed that the active site always cannot accommodate the dye molecules, due to constricted
nature of the active site pocket and steric hindrance of the residues whereas mediators are relatively small and can easily
be accommodated into the active site pocket, which, thereafter leads to the productive binding. The binding properties of
these compounds along with identification of critical active site residues can be used for further site-directed mutagenesis
experiments in order to identify their role in activity and substrate specificity, ultimately leading to improved mutants
for degradation of these toxic compounds. 相似文献
77.
78.
Bowden MG Heuck AP Ponnuraj K Kolosova E Choe D Gurusiddappa S Narayana SV Johnson AE Höök M 《The Journal of biological chemistry》2008,283(1):638-647
Staphylococcus epidermidis is an opportunistic pathogen and a major cause of foreign body infections. The S. epidermidis fibrinogen (Fg)-binding adhesin SdrG is necessary and sufficient for the attachment of this pathogen to Fg-coated materials. Based largely on structural analyses of the ligand binding domain of SdrG as an apo-protein and in complex with a Fg-like peptide, we proposed that SdrG follows a "dock, lock, and latch" mechanism to bind to Fg. This binding mechanism involves the docking of the ligand in a pocket formed between two SdrG subdomains followed by the movement of a C-terminal extension of one subdomain to cover the ligand and to insert and complement a beta-sheet in a neighboring subdomain. These proposed events result in a greatly stabilized closed conformation of the MSCRAMM-ligand complex. In this report, we describe a biochemical analysis of the proposed conformational changes that SdrG undergoes upon binding to its ligand. We have introduced disulfide bonds into SdrG to stabilize the open and closed forms of the apo-form of the MSCRAMM. We show that the stabilized closed form does not bind to the ligand and that binding can be restored in the presence of reducing agents such as dithiothreitol. We have also used F?rster resonance energy transfer to dynamically show the conformational changes of SdrG upon binding to its ligand. Finally, we have used isothermic calorimetry to determine that hydrophobic interactions between the ligand and the protein are responsible for re-directing the C-terminal extension of the second subdomain required for triggering the beta-strand complementation event. 相似文献
79.
80.
TMPyP4 (Mesotetra(N-methyl-4-pyridyl)porphine) is known to have a high affinity for G-quadruplex DNA. However, there is still some controversy over the exact site(s) and mode(s) of TMPyP4 binding to G-quadruplex DNA. We examined TMPyP4 interactions with seven G-quadruplex forming oligonucleotides. The parent oligonucleotide is a 27-mer with a wild-type (WT) G-rich sequence of the Bcl-2 P1 promoter mid-region (5′-d(CGG GCG CGG GAG GAA GGG GGC GGG AGC-3′)). This sequence folds into at least three unique loop isomer quadruplexes. The two mutant oligonucleotides used in this study are shorter (23-mer) sequences in which nonquadruplex core bases were eliminated and two different (-G-G-) → (-T-T-) substitutions were made to restrict the folding complexity. The four additional mutant oligonucleotides were labeled by substituting a 2-aminopurine (2-AP) base for an A or G in either the first three-base lateral loop or the second five- or seven-base lateral loop (depending on the G→T mutation positions). Spectroscopic and microcalorimetric studies indicate that four molecules of TMPyP4 can be bound to a single G-quadruplex. Binding of the first two moles of TMPyP4 appears to occur by an end or exterior mode (K ≈ 1 × 107 M−1), whereas binding of the third and fourth moles of TMPyP4 appears to occur by a weaker, intercalative binding mode (K ≈ 1 × 105 M−1). As the mid-loop size decreases from seven to five bases, end binding occurs with significantly increased affinity. 2-AP-labeled Bcl-2 promoter region quadruplexes show increased fluorescence of the 2-AP base on addition of TMPyP4. The change in fluorescence for 2-AP bases in the second half of the TMPyP4 titration lends support to our previous speculation regarding the intercalative nature of the weaker binding mode. 相似文献