Traditional data structures

Chương 4 – Các cấu trúc dữ liệu. Chương này cung cấp cho người học những nội dung chính sau: Các mức biểu diễn dữ liệu hình ảnh, traditional data structures, hierarchical data structures. Mời các bạn cùng tham khảo để biết thêm các nội dung chi tiết.

51p tangtuy20 22-07-2016 26 5   Download

The human b-globin gene locus is the subject of intense study, and over the past two decades a wealth of information has accumulated on how tissue-specific and stage-specific expression of its genes is achieved. The data are extensive and it would be difficult, if not impossible, to formulate a comprehensive model integrating every aspect of what is currently known. In this review, we introduce the fundamental characteristics of globin locus regulation as well as questions on which much of the current research is predicated.

11p system191 01-06-2013 50 4   Download

The design of b-glycosidases with planed substrate specificity for biotechnological application has received little attention. This is mostly a consequence of the lack of data on the molecular basis of the b-glycosidase specificity, namely data on the energy of the noncovalent interactions in the enzymetransition state complex. In an attempt to fill this gap, sitedirected mutagenesis and enzyme steady-state kinetic experiments with different substrates were conducted, using as model a digestive b-glycosidase (glycoside hydrolase family 1) from Spodoptera frugiperda (Lepidoptera) (Sfbgly50).

10p system191 01-06-2013 45 4   Download

The case of homologous monomeric c-type and oligomeric b-type crystallins has been described and analyzed in evolutionary terms. Data and hypotheses from molecular genetics and structural investigations converge and suggest a novel three-phase model for the evolutionary history of crystallin-type proteins. In the divergent cascades of monomeric and oligomeric crystallins, a pivotal role was played by alterations in the gene segments encoding the C-terminal extensions and the intermotif or interdomain linker peptides.

9p system191 01-06-2013 43 4   Download

Previous data showing an increase of receptor binding activity of [R16]VIP, a vasoactive intestinal peptide (VIP) structural analogue containing arginine at the position 16 of its amino acid sequence, have pointed out the importance of a positive charge at this site. Here, the functional characterization of three VIP polyaminated adducts (VIPDap, VIPSpd, and VIPSpm), obtained by a transglutaminasecatalysed reaction between the VIP Gln16 residue and 1,3-diaminopropane (Dap), spermidine (Spd), or spermine (Spm), is reported. ...

9p system191 01-06-2013 42 4   Download

The expression of mitochondrial and hydrogenosomal ADP/ATP carriers (AACs) from plants, rat and the anaerobic chytridiomycete fungus Neocallimastix spec. L2 in Escherichia coli allows a functional integration of the recombinant proteins into the bacterial cytoplasmic membrane. For AAC1 and AAC2 from rat, apparent Km values of about 40 lM for ADP, and 105 lM or 140 lM, respectively, for ATP have been determined, similar to the data reported for isolated rat mitochondria.

10p system191 01-06-2013 37 3   Download

Comparative analysis of genome sequence data from mesophilic and hyperthermophilic micro-organisms has revealed a strong bias against specific thermolabile aminoacid residues (i.e. N and Q) in hyperthermophilic proteins. The N þ Q content of class II xylose isomerases (XIs) from mesophiles, moderate thermophiles, and hyperthermophiles was examined.

11p system191 01-06-2013 30 4   Download

The solution structure of the growth factor chimera mEGF/ TGFa44250 has been determined using an extended version of the DYANA procedure for calculating structures from NMR data. The backbone fold and preferred orientation of the domains of the chimera are similar to those found in previous studies of EGF structures, and several H-bonds used as input constraints in those studies were found independently in the chimera. This shows that the modified activity of the chimera does not result from a major structural change.

9p system191 01-06-2013 45 4   Download

Murine double minute 2 (MDM2) protein exhibits many diverse biochemi-cal functions on the tumour suppressor protein p53, including transcrip-tional suppression and E3 ubiquitin ligase activity. However, more recent data have shown that MDM2 can exhibit ATP-dependent molecular chap-erone activity and directly mediate folding of the p53 tetramer. Analysing the ATP-dependent function of MDM2 will provide novel insights into the evolution and function of the protein.

12p research12 29-04-2013 61 4   Download

The Rv0948c gene fromMycobacterium tuberculosisH37Rv encodes a 90 amino acid protein as the natural gene product with chorismate mutase (CM) activity. The protein, 90-MtCM, exhibits Michaelis–Menten kinetics with akcat of 5.5 ± 0.2 s )1 and a Kmof 1500 ± 100lmat 37C and pH 7.5. The 2.0 A˚ X-ray structure shows that 90-MtCM is an alla-helical homodimer (Protein Data Bank ID: 2QBV) with the topology ofEscheri-chia coliCM (EcCM), and that both protomers contribute to each catalytic site.

12p research12 29-04-2013 39 3   Download

This studywas designed to yield data on the supramolecular organization of the phycobilisome apparatus from Synechocystis, and the possible effects of environmental stress on this arrangement. Phycobilisomes were dissociated ina low ionic strength solutionandaquantitative estimation of the protein components present in each subcomplex was obtained using liquid chromatography coupled on-line with a mass spectrometer equipped with an electrospray ion source (ESI-MS).

9p research12 29-04-2013 50 3   Download

The photosynthetic protein complexes in plants are located in the chloroplast thylakoid membranes. These membranes have an ultrastructure that consists of tightly stackedÔgranaÕ regions interconnectedbyunstackedmembrane regions.The structure of isolated granamembranes has been studiedhere by cryo-electron microscopy. The data reveals an unusual arrangement of the photosynthetic protein complexes, staggered over two tightly stacked planes.

11p research12 29-04-2013 42 2   Download

Pisum sativump16 is a protein present in the chromatin of ungerminated embryonic axes. The purification of p16 and the isolationof a cDNAclone ofpsp54, the gene encoding its precursor have been recently reported [Castillo, J., Rodrigo, M. I.,Ma´rquez, J. A., Zu´n˜iga, AandFranco, L. (2000)Eur. J.Biochem.267, 2156–2165]. In thepresentpaper,wepresent data showing that p16 is a nuclear protein.

8p research12 23-04-2013 38 2   Download

Glycosylatedpolyenemacrolide antibiotics, as nystatins and amphotericins, are amphiphilic structures known to exert antifungal activity by disrupting the fungal cell membrane, leading to leakage of cellular materials, and cell death. This membrane disruption is strongly influenced by the presence and the exact nature of the membrane sterols.

9p research12 23-04-2013 39 2   Download

The complete coding sequence of a BDIX rat gene homo-logous to the human ABO gene was determined. Identifi-cation of the exon–intron boundaries, obtained by comparison of the coding sequence with rat genomic sequences from data banks, revealed that the rat gene structure is identical to that of the human ABO gene. It localizes to rat chromosome 3 (q11-q12), a region homolo-gous to human 9q34.

8p research12 23-04-2013 39 2   Download

Trihaem cytochromec3 (also known as cytochrome c551.5 and cytochromec7 ) is isolated fromthe periplasmic space of Desulfuromonas acetoxidans, a sulfur-reducing bacterium. Thermodynamic and kinetic data for the trihaem cyto-chromec3are presented and discussed in the context of the possible physiological implications of its functional proper-ties with respect to the natural habitat of D. acetoxidans, namelyas a symbiontwithgreensulfurbacteriaworkingas a mini-sulfuretum.

9p tumor12 22-04-2013 36 4   Download

Mature, active mammalian histidine decarboxylase is a di-meric enzyme of carboxy-truncatedmonomers (
53 kDa). By using a biocomputational approach, we have generateda three-dimensional model of a recombinant 1/512 fragment of the rat enzyme, which shows kinetic constants similar to those of the mature enzyme purified from rodent tissues. This model, together with previous spectroscopic data, al-lowed us to postulate that the occupation of the catalytic center by the natural substrate, or by substrate-analogs, would induce remarkable changes in the conformation of the intact holoenzyme....

12p tumor12 20-04-2013 37 2   Download

We examined the microenvironment of the single trypto-phan and the tyrosine residues of PsbQ, one of the three main extrinsic proteins of green algal and higher plant photosystem II. On the basis of this information and the previous data on secondary structure [Balsera, M., Arel-lano, J.B., Gutie´rrez, J.R., Heredia, P., Revuelta, J.L. & De Las Rivas, J. (2003)Biochemistry42, 1000–1007], we screened structural models derived by combining various threading approaches.

12p tumor12 20-04-2013 33 1   Download

Even though more than 200 three-dimensional structures of HIV-1 protease complexed to a variety of inhibitors are available in the Protein Data Bank; very few struc-tures of unliganded protein have been determined. We have recently solved structures of unliganded HIV-1 protease tethered dimer mutants to resolutions of 1.9 A˚ and 2.1 A ˚ , and have found that the flaps assume closed-flap conformation even in the absence of any bound lig-and.

9p tumor12 20-04-2013 22 2   Download

NMR spectroscopy and X-ray crystallography have provi-ded important insight into structural features of phenyl-alanine hydroxylase (PAH) and tyrosine hydroxylase (TH). Nevertheless, significant problems such as the substrate specificity of PAHand the different susceptibility of TH to feedback inhibition by L-3,4-dihydroxyphenylalanine (L-DOPA) compared with dopamine (DA) remain unre-solved.

11p tumor12 20-04-2013 52 3   Download