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Rice is a staple food source and therefore widely planted by farmers. Straw is a residual waste of rice harvests which has not been utilized optimally. This residual waste can be used in semi-finished products and finished products, especially crafts and furniture for the export market. This study considers the use of waste straw for the needs of the handicraft industry and mining. The second objective is furniture and craft design innovation using a straw. Experiments were carried out by twisting straw so that it becomes a certain diameter and length. The upland variety of slegereng red rice straw was the research object owing to its greater length and hgher strength than other types. Data was derived from literature and informants, and evaluated using interactive analysis models, including data reduction, data display and data verification. The study demonstrates that waste straw can be used in furniture and craft product design innovations. The application is on chairs, tables, stools, tissue boxes, table lamps, frames and so on. [ABSTRACT FROM AUTHOR]

The existing vaccines against influenza are based on the generation of neutralizing antibody primarily directed against surface proteins - hemagglutinin and neuraminidase. In this work, we have computationally defined conserved T cell epitopes of proteins of influenza virus H5N1 to help in the design of a vaccine with haplotype specificity for a target population. The peptides from the proteome of H5N1 virus which are predicted to bind to different HLAs, do not show similarity with peptides of human proteome and are also identified to be generated by proteolytic cleavage. These peptides could be made use of in the design of either a DNA vaccine or a subunit vaccine against influenza.

Mycobacterium smegmatis RecA and its nucleotide complexes crystallize in three different, but closely related, forms characterized by specific ranges of unit cell dimensions. The six crystals reported here and five reported earlier, all grown under the same or very similar conditions, belong to these three forms, all in space group P6(1). They include one obtained by reducing relative humidity around the crystal. In all crystals, RecA monomers form filaments around a 6(1) screw axis. Thus, the c-dimension of the crystal corresponds to the pitch of the RecA filament. As reported for Escherichia coli RecA, the variation in the pitch among the three forms correlates well with the motion of the C-terminal domain of the RecA monomers with respect to the main domain. The domain motion is compatible with formation of inactive as well as active RecA filaments involving monomers with a fully ordered C domain. It does not appear to influence the movement upon nucleotide-binding of the switch residue, which is believed to provide the trigger for transmitting the effect of nucleotide binding to the DNA-binding region. Interestingly, partial dehydration of the crystal results in the movement of the residue similar to that caused by nucleotide binding. The ordering of the DNA-binding loops, which present ensembles of conformations, is also unaffected by domain motion. The conformation of loop L2 appears to depend upon nucleotide binding, presumably on account of the movement of the switch residue that forms part of the loop. The conformations of loops L1 and L2 are correlated and have implications for intermolecular communications within the RecA filament. The structures resulting from different orientations of the C domain and different conformations of the DNA-binding loops appear to represent snapshots of the RecA at different phases of activity, and provide insights into the mechanism of action of RecA.

The role of secretory proteins of Mycobacterium tuberculosis in pathogenesis and stimulation of specific host responses is well documented. They are also shown to activate different cell types, which subsequently present mycobacterial antigens to T cells. Therefore identification of T cell epitopes from this set of proteins may serve to define candidate antigens with vaccine potential. Fifty-two secretory proteins of M. tuberculosis H37Rv were analyzed computationally for the presence of HLA class I binding nonameric peptides. All possible overlapping nonameric peptide sequences from 52 secretory proteins were generated in silico and analyzed for their ability to bind to 33 alleles belonging to A, B and C loci of HLA class I. Fifteen percent of generated peptides are predicted to bind to HLA with halftime of dissociation T(1/2) >or=100 min and 73% of the peptides predicted to bind are mono-allelic in their binding. The structural basis for recognition of no-namers by different HLA molecules was studied employing structural modeling of HLA class I-peptide complexes and there exists a good correlation between structural analysis and binding prediction. Pathogen peptides that could behave as self- or partially self-peptides in the host were eliminated using a comparative study with the human proteome, thus reducing the number of peptides for analysis. The implications of the finding for vaccine development are discussed vis-à-vis the limitations of the use of subunit vaccine and DNA vaccine.

Knowledge of structural relationships in proteins is increasingly proving very useful for in silico characterizations and is also being exploited as a prelude to almost every investigation in functional and structural genomics. A thorough understanding of the crucial features of a fold becomes necessary to realize the full potential of such relationships. To illustrate this, structures containing the legume lectin-like fold were chosen for a detailed analysis since they exhibit a total lack of sequence similarity among themselves and also belong to diverse functional families. A comparative analysis of 15 different families containing this fold was therefore carried out, which led to the determination of the minimal structural principles or the determining region of the fold. A critical evaluation of the structural features, such as the curvature of the front sheet, the presence of the hydrophobic cores and the binding site loops, suggests that none of them are crucial for either the formation or the stability of the fold, but are required to generate diversity and specificity to particular carbohydrates. In contrast, the presence of the three sheets in a particular geometry and also their topological connectivities seem to be important. The fold has been shown to tolerate different types of protein-protein associations, most of them exhibiting different types of quaternary associations and some even existing as complexes with other folds. The function of every family in this study is discussed with respect to its fold, leading to the suggestion that this fold can be linked to carbohydrate recognition in general.

Mannose, an abundant cell surface monosaccharide binds to a diverse set of receptors, which are involved in a variety of important cellular processes. Structural analysis has been carried out on all the proteins containing non-covalently bound mannose as a monosaccharide in the Protein Data Bank, to identify common recognition principles. Proteins, highly specific to mannose, belonging to the super family of bulb lectins, are found to contain a consensus sequence motif QXDXNXVXY, which has been identified to be essential for mannose binding. Analysis of this motif in the crystal structures of bulb lectins has led to the understanding of the contribution of individual residues in mannose recognition. Comparison with other mannose binding proteins, reveals common hydrogen bonding patterns in all of them, despite differences in sequence, overall fold and the substructures at the binding sites of individual proteins. A database analysis also suggests that although the topology of the backbone, as at the binding site in bulb lectins, can generate mannose binding capability in a few other proteins, sequence and disposition of not only the residues in the motif, but also the residues in the neighborhood play a crucial role in allowing that property to be retained.

A mannose-specific agglutinin, isolated from garlic bulbs, has been crystallized in the presence of a large excess of alpha-d-mannose, in space group C2 and cell dimensions, a=203.24, b=43.78, c=79.27 A, beta=112.4 degrees, with two dimers in the asymmetric unit. X-ray diffraction data were collected up to a nominal resolution of 2.4 A and the structure was solved by molecular replacement. The structure, refined to an R-factor of 22.6 % and an Rfree of 27.8 % reveals a beta-prism II fold, similar to that in the snowdrop lectin, comprising three antiparallel four-stranded beta-sheets arranged as a 12-stranded beta-barrel, with an approximate internal 3-fold symmetry. This agglutinin is, however, a dimer unlike snowdrop lectin which exists as a tetramer, despite a high degree of sequence similarity between them. A comparison of the two structures reveals a few substitutions in the garlic lectin which stabilise it into a dimer and prevent tetramer formation. Three mannose molecules have been identified on each subunit. In addition, electron density is observed for another possible mannose molecule per dimer resulting in a total of seven mannose molecules in each dimer. Although the mannose binding sites and the overall structure are similar in the subunits of snowdrop and garlic lectin, their specificities to glycoproteins such as GP120 vary considerably. These differences appear, in part, to be a direct consequence of the differences in oligomerisation, implying that variation in quaternary association may be a mode of achieving oligosaccharide specificity in bulb lectins., (Copyright 1998 Academic Press.)

Amino acid - carboxylic acid complexes provide useful information in relation to molecular interactions in present day biological systems and to prebiotic self-organisation. The crystal structures of the complexes of maleic acid with DL- arginine (orthorhombic; Pca2(1); a=15.9829, b=5.4127, c=16.1885; R=0.0522 for 956 reflections) and L- arginine (triclinic; P1; a=5.2641, b=8.0388, c=9.7860, alpha=106.197, beta=97.275, gamma=101.64; R=0.039 for 1749 reflections) have been determined. The complexes are made up of positively charged zwitterionic arginine molecules and negatively charged semi-maleate ions which contain an intramolecular symmetric O-H-O hydrogen bond. In both the structures, the amino acid molecules aggregate into layers. In each layer, S2 head-to-tail sequences are interconnected through specific intermolecular interactions between alpha-carboxylate and guanidyl groups, an arrangement observed for the first time in crystal structures involving arginine. The carboxylate-guanidyl interactions are of different types in the two complexes and consequently aggregation patterns in them exhibit substantial differences. Interactions between the amino acid layers involve the semi-maleate ions in both the complexes. In addition, water-bridges also exist in the L complex. The full potential of the guanidyl group for specific interactions is realized in both the structures. The L complex contains an array of water-mediated salt bridges. The structures demonstrate that the effect of chirality on molecular aggregation can span a wide range.

The occurrence of large domain motions associated with the mechanism of action of many proteins is well established. We present a general method of predicting domain closure applicable to proteins containing domains separated by an apparent hinge. The method attempts to allow for natural directional bias within the closing protein by repeatedly applying a weak pulling force over a short distance between pairs of atoms chosen at random in the two domains in question. Appropriate parameters governing the pulling function were determined empirically. The method was applied to the bi-lobal protein PGK and a closed-form activated ternary complex generated for Bacillus stearothermophilus PGK. This model was compared with the recently determined crystal structure of closed-form Trypanosoma brucei PGK. The model predicts the correct hinge regions, although the magnitude of movement at one hinge point was overestimated, and provides a reasonable representation of the closed-form ternary complex.

The recA locus of pathogenic mycobacteria differs from that of nonpathogenic species because it contains large intervening sequences nested in the RecA homology region that are excised by an unusual protein-splicing reaction. In vivo assays indicated that Mycobacterium tuberculosis recA partially complemented Escherichia coli recA mutants for recombination and mutagenesis. Further, splicing of the 85 kDa precursor to 38 kDa MtRecA protein was necessary for the display of its activity, in vivo. To gain insights into the molecular basis for partial and lack of complementation by MtRecA and 85 kDa proteins, respectively, we purified both of them to homogeneity. MtRecA protein, but not the 85 kDa form, bound stoichiometrically to single-stranded DNA in the presence of ATP. MtRecA protein was cross-linked to 8-azidoadenosine 5'-triphosphate with reduced efficiency, and kinetic analysis of ATPase activity suggested that it is due to decreased affinity for ATP. In contrast, the 85 kDa form was unable to bind ATP, in the presence or absence of ssDNA and, consequently, was entirely devoid of ATPase activity. Molecular modeling studies suggested that the decreased affinity of MtRecA protein for ATP and the reduced efficiency of its hydrolysis might be due to the widening of the cleft which alters the hydrogen bonds and the contact area between the enzyme and the substrate and changes in the disposition of the amino acid residues around the magnesium ion and the gamma-phosphate. The formation of joint molecules promoted by MtRecA protein was stimulated by SSB when the former was added first. The probability of an association between the lack and partial levels of biological activity of RecA protein(s) to that of illegitimate recombination in pathogenic mycobacteria is considered.