Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method of semiempirical identification of structural domains is proposed. The procedure is based on the comparison of amino acid sequences in groups of homologous proteins. This approach was tested using 32 known protein sequences from different cytochrome b5, cytochrome c, lysozyme, hemoglobin, and myoglobin proteins. The method presented was able to identify all structural domains of these reference proteins. A consensus secondary structure provided information on structural content of these domains predicting correctly 21 of 23 (91%) of alpha-helices. We applied this method to six homologous phytochrome sequences from Avena, Arabadopsis, Cucurbita, Maize, Oryza, and Pisum. Some of the identified domains can be assigned to the known tertiary structure categories. For example, an alpha/beta domain is localized in the region known to stabilize the phytochrome chromophore in the red light absorbing form (Pr). One alpha-helical and one alpha/beta domains are localized in regions important for the chromophore stabilization in the far-red absorbing form (Pfr). From an analysis of noncovalent interaction patterns in another domain it is proposed that a phytochrome dimer contact involves two segments localized between residues 730 and 821 (using numbering of aligned sequences). Also, a possible antiparallel beta-sheet structure of this region has been suggested. According to this model, the long axis of the interacting structures is perpendicular to a twofold symmetry axis of the phytochrome dimer.
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PMID:Structural domains of phytochrome deduced from homologies in amino acid sequences. 132 84

The recovery of a recombinant intracellular protein, cytochrome b5, from Escherichia coli TB1 cells was carried out by bead mill disintegration in a discontinuous small-scale instrument. This process was optimized by the use of experimental factorial design. Several parameters were studied: operating time, amount and size of beads, cellular suspension concentration, and presence of toluene and lysozyme. For the experimental conditions used, only the time of treatment and bead load had significant effects. The optimal values of these variables were found by applying the response surface methodology.
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PMID:Optimization study of Escherichia coli TB1 cell disruption for cytochrome b5 recovery in a small-scale bead mill. 885 89

Important and relevant information is expected to be encoded in local structural elements of proteins. An unsupervised learning algorithm (Kohonen algorithm) was applied to the representation and unbiased classification of local backbone structures contained in a set of proteins. Training yielded a two-dimensional Kohonen feature map with 100 different structural motifs including certain helical and strand structures. All motifs were represented in a phi-psi-plot and some of them as a three-dimensional model. The course of structural motifs along the backbone of four selected proteins (cytochrome b5, cytochrome b562, lysozyme, gamma crystallin) was investigated in detail. Trajectories and histograms visualizing the abundance of characteristic motifs allowed for the distinction between different types of protein overall folds. It is demonstrated how the histograms may be used to construct a structural similarity matrix for proteins. The Kohonen algorithm provides a simple procedure for classification of local protein structures independent of any a priori knowledge of leading structural motifs. Training of the Kohonen network leads to the generation of "consensus structures' serving for the task of classification.
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PMID:Local structural motifs of protein backbones are classified by self-organizing neural networks. 893 Nov 22

Using new flight hardware, a Chinese mission of space protein crystallization has been performed aboard the Chinese spacecraft SZ-3. Preliminary analyses of the experimental results have shown that a few proteins produced better crystals in space. At least, the crystals of cytochrome b5 mutant could diffract X-ray beyond the highest resolution reported so far for the same kind of crystals. In addition, some rules derived from our numerical studies of the liquid/liquid diffusion protein crystallization were proved by the crystallization of lysozyme as model protein in this space experiment, which also clearly showed the advantages and disadvantages of the gelation of the protein solution used in microgravity growth of protein crystals.
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PMID:The space experiment of protein crystallization aboard the Chinese spacecraft SZ-3. 1465 52