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91.
Solution structure of the phosphocarrier protein HPr from Bacillus subtilis by two-dimensional NMR spectroscopy. 总被引:6,自引:5,他引:1 下载免费PDF全文
M. Wittekind P. Rajagopal B. R. Branchini J. Reizer M. H. Saier Jr R. E. Klevit 《Protein science : a publication of the Protein Society》1992,1(10):1363-1376
The solution structure of the phosphocarrier protein, HPr, from Bacillus subtilis has been determined by analysis of two-dimensional (2D) NMR spectra acquired for the unphosphorylated form of the protein. Inverse-detected 2D (1H-15N) heteronuclear multiple quantum correlation nuclear Overhauser effect (HMQC NOESY) and homonuclear Hartmann-Hahn (HOHAHA) spectra utilizing 15N assignments (reported here) as well as previously published 1H assignments were used to identify cross-peaks that are not resolved in 2D homonuclear 1H spectra. Distance constraints derived from NOESY cross-peaks, hydrogen-bonding patterns derived from 1H-2H exchange experiments, and dihedral angle constraints derived from analysis of coupling constants were used for structure calculations using the variable target function algorithm, DIANA. The calculated models were refined by dynamical simulated annealing using the program X-PLOR. The resulting family of structures has a mean backbone rmsd of 0.63 A (N, C alpha, C', O atoms), excluding the segments containing residues 45-59 and 84-88. The structure is comprised of a four-stranded antiparallel beta-sheet with two antiparallel alpha-helices on one side of the sheet. The active-site His 15 residue serves as the N-cap of alpha-helix A, with its N delta 1 atom pointed toward the solvent to accept the phosphoryl group during the phosphotransfer reaction with enzyme I. The existence of a hydrogen bond between the side-chain oxygen atom of Tyr 37 and the amide proton of Ala 56 is suggested, which may account for the observed stabilization of the region that includes the beta-turn comprised of residues 37-40. If the beta alpha beta beta alpha beta (alpha) folding topology of HPr is considered with the peptide chain polarity reversed, the protein fold is identical to that described for another group of beta alpha beta beta alpha beta proteins that include acylphosphatase and the RNA-binding domains of the U1 snRNP A and hnRNP C proteins. 相似文献
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Sven Ruf Mahanandeesha Siddappa Hallur Nisha K. Anchan Indu N. Swamy Karthikai Raj Murugesan Sayantani Sarkar Lokesh Kananti Narasimhulu V.P. Rama Kishore Putta Shama Shaik Devaraj Venkatapura Chandrasekar Vishal Subhash Mane Sanjay Venkatachalapathi Kadnur Juluri Suresh Ravi Kanth Bhamidipati Manvi Singh Raghunadha Reddy Burri Rajendra Kristam Herman Schreuder Sridharan Rajagopal 《Bioorganic & medicinal chemistry letters》2018,28(5):922-925
Nicotinamide N-methyltransferase (NNMT) has been linked to obesity and diabetes. We have identified a novel nicotinamide (NA) analog, compound 12 that inhibited NNMT enzymatic activity and reduced the formation of 1-methyl-nicotinamide (MNA), the primary metabolite of NA by ~80% at 2?h when dosed in mice orally at 50?mg/kg. 相似文献
94.
Balaji Prakash S. Selvaraj M. R. N. Murthy Y. N. Sreerama D. Rajagopal Rao Lalitha R. Gowda 《Journal of molecular evolution》1996,42(5):560-569
Plant seeds contain a large number of protease inhibitors of animal, fungal, and bacterial origin. One of the well-studied
families of these inhibitors is the Bowman-Birk family(BBI). The BBIs from dicotyledonous seeds are 8K, double-headed proteins.
In contrast, the 8K inhibitors from monocotyledonous seeds are single headed. Monocots also have a 16K, double-headed inhibitor.
We have determined the primary structure of a Bowman-Birk inhibitor from a dicot, horsegram, by sequential edman analysis
of the intact protein and peptides derived from enzymatic and chemical cleavage. The 76-residue-long inhibitor is very similar
to that ofMacrotyloma axillare. An analysis of this inhibitor along with 26 other Bowman-Birk inhibitor domains (MW 8K) available in the SWISSPROT databank
revealed that the proteins from monocots and dicots belong to related but distinct families. Inhibitors from monocots show
larger variation in sequence. Sequence comparison shows that a crucial disulphide which connects the amino and carboxy termini
of the active site loop is lost in monocots. The loss of a reactive site in monocots seems to be correlated to this. However,
it appears that this disulphide is not absolutely essential for retention of inhibitory function. Our analysis suggests that
gene duplication leading to a 16K inhibitor in monocots has occurred, probably after the divergence of monocots and dicots,
and also after the loss of second reactive site in monocots.
S. Selvaraj is on leave from Department of Physics, Bharathidasan University, Tiruchirapalli 620 024, Tamilnadu, India
Correspondence to: M.R.N. Murthy 相似文献
95.
Vladimir Tsuprun Basavapatna S. Rajagopal Dwight Anderson 《Journal of structural biology》1995,115(3)
The Bacillus subtilis GroESL chaperonin was isolated by sucrose density gradient centrifugation and the constituent GroES and GroEL moieties were purified by electrophoresis in agarose. Electron microscopic images of negatively stained GroEL and GroES oligomers and GroESL complexes were averaged using a reference-free alignment method. The GroEL and GroES particles had the sevenfold symmetry characteristic of their Escherichia coli counterparts. GroESL complexes, reconstituted efficiently in vitro from GroEL and GroES in the absence of added ADP or ATP, had the characteristic bullet- and football-like shapes in side view. Purified bacteriophage φ29 head-tail connectors having a mass in excess of 0.4 MDa were shown to bind to GroESL at the end opposite to the GroES. The same GroESL-connector complexes were isolated from phage-infected cells in which capsid assembly was blocked, and thus the complex may have functional significance in φ29 morphogenesis. 相似文献
96.
Seasonal distribution and community succession of macrofoulants were studied using concrete panels in the coastal waters of Kalpakkam, east coast of India, for a period of two years. The panels were suspended at 1 m, 4 m and 7 m depths and categorised into short-term and long-term exposures. A high total of 105 fouling taxa were recorded. The major fouling organisms observed were hydroids, barnacles, mussels, anthozoans and ascidians. Considerable faunistic and biomass variations were noticed both with respect to season and depth. The month of panel exposure had a significant influence on the succession of fouling communities. On the short-term panels, the maximum fouling biomass was 64 kg m–2 in 30 days at 4 m depth, whereas on the long-term panels, it was 250 kg m–2 after 216 days at 4 m depth. A comparison with the biomass values reported from elsewhere shows that biomass build-up in Kalpakkam coastal waters is one of the highest ever reported. Such a very high biomass accumulation is due to the extremely dense settlement of mussels, especially the green mussel,Perna viridis (L). 相似文献
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99.
Preparation and Properties of Antibodies against Indoleacetic Acid (IAA)-C5-BSA, a Novel Ring-Coupled IAA Antigen, as Compared to Two Other Types of IAA-Specific Antibodies 下载免费PDF全文
Two types of indoleacetic acid (IAA) antigens have been described in the literature which show marked differences with respect to antibody specificity. In this communication an alternative antigen design is described. In the so-called IAA-C5-BSA conjugate, both the acetic acid group and the pyrrole moiety are presented free, as the covalent linkage between IAA and the carrier molecule is introduced in the benzene moiety. Antibodies were elicited in rabbits against this novel antigen. Using cross-reactivity data and the strategy of successive approximation for the measurements of auxin levels in the internodes of light-grown broad bean (Vicia faba L. cv Superfine), the three types of antibodies are compared. 相似文献
100.
By the use of a new trick, the open one-dimensional Ising model with nearest neighbor interactions is solved exactly to examine impurity and end effects on finite polymer chains. Melting curves are plotted for various distributions of AT and GC bonds as a function of interaction strength and chain length. Results are compared with previous calculations on infinite length chains by Montroll &; Goel. Correlation effects between impurity bonds on a finite, pure-basis chain are also studied and their implications to further studies of polymer chains indicated. 相似文献