• Title/Summary/Keyword: Molecular searching

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Recent Development of Search Algorithm on Small Molecule Docking (소분자 도킹에서의 탐색알고리듬의 현황)

  • Chung, Hwan Won;Cho, Seung Joo
    • Journal of Integrative Natural Science
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    • v.2 no.2
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    • pp.55-58
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    • 2009
  • A ligand-receptor docking program is an indispensible tool in modern pharmaceutical design. An accurate prediction of small molecular docking pose to a receptor is essential in drug design as well as molecular recognition. An effective docking program requires the ability to locate a correct binding pose in a surprisingly complex conformational space. However, there is an inherent difficulty to predict correct binding pose. The odds are more demanding than finding a needle in a haystack. This mainly comes from the flexibility of both ligand and receptor. Because the searching space to consider is so vast, receptor rigidity has been often applied in docking programs. Even nowadays the receptor may not be considered to be fully flexible although there have been some progress in search algorithm. Improving the efficiency of searching algorithm is still in great demand to explore other applications areas with inherently flexible ligand and/or receptor. In addition to classical search algorithms such as molecular dynamics, Monte Carlo, genetic algorithm and simulated annealing, rather recent algorithms such as tabu search, stochastic tunneling, particle swarm optimizations were also found to be effective. A good search algorithm would require a good balance between exploration and exploitation. It would be a good strategy to combine algorithms already developed. This composite algorithms can be more effective than an individual search algorithms.

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3D Shape Descriptor with Interatomic Distance for Screening the Molecular Database (분자 데이터베이스 스크리닝을 위한 원자간 거리 기반의 3차원 형상 기술자)

  • Lee, Jae-Ho;Park, Joon-Young
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.6
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    • pp.404-414
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    • 2009
  • In the computational molecular analysis, 3D structural comparison for protein searching plays a very important role. As protein databases have been grown rapidly in size, exhaustive search methods cannot provide satisfactory performance. Because exhaustive search methods try to handle the structure of protein by using sphere set which is converted from atoms set, the similarity calculation about two sphere sets is very expensive. Instead, the filter-and-refine paradigm offers an efficient alternative to database search without compromising the accuracy of the answers. In recent, a very fast algorithm based on the inter-atomic distance has been suggested by Ballester and Richard. Since they adopted the moments of distribution with inter-atomic distance between atoms which are rotational invariant, they can eliminate the structure alignment and orientation fix process and perform the searching faster than previous methods. In this paper, we propose a new 3D shape descriptor. It has properties of the general shape distribution and useful property in screening the molecular database. We show some experimental results for the validity of our method.

Informatics for protein identification by tandem mass spectrometry; Focused on two most-widely applied algorithms, Mascot and SEQUEST

  • Sohn, Chang-Ho;Jung, Jin-Woo;Kang, Gum-Yong;Kim, Kwang-Pyo
    • Bioinformatics and Biosystems
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    • v.1 no.2
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    • pp.89-94
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    • 2006
  • Mass spectrometry (MS) is widely applied for high throughput proteomics analysis. When large-scale proteome analysis experiments are performed, it generates massive amount of data. To search these proteomics data against protein databases, fully automated database search algorithms, such as Mascot and SEQUEST are routinely employed. At present, it is critical to reduce false positives and false negatives during such analysis. In this review we have focused on aspects of automated protein identification using tandem mass spectrometry (MS/MS) spectra and validation of the protein identifications of two most common automated protein identification algorithms Mascot and SEQUEST.

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An Oligonucleotide Microarray Bait for Isolation of Target Gene Fragments

  • Shi, Rong;Ma, Wen-li;Liu, Cui-Hua;Song, Yan-Bin;Mao, Xiang-Ming;Zheng, Wen-Ling
    • BMB Reports
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    • v.37 no.2
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    • pp.148-152
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    • 2004
  • A new molecular-baiting method was studied by retrieving targeted gene fragments from an oligonucleotide microarray bait after hybridization. To make the microarray bait, 70-mer oligonucleotides that were designed to specifically represent the SSA1 gene of Saccharomyces cerevisiae were printed on the slide. Samples of the Saccharomyces cerevisiae mRNA were extracted and labeled by the RD-PCR (Restriction Display PCR) method using the Cy5-labelled universal primer, then applied for hybridization. The sample fragments that hybridized to the microarray were stripped, and the eluted cDNAs were retrieved and cloned into the pMD 18-T vector for transformation, plasmid preparation, and sequencing. BLAST searching of the GenBank database identified the retrieved fragments as being identical to the SSA1 gene (from 2057-2541bp). A new method is being established that can retrieve the sample fragments using an oligo-microarray-bait.

The Molecular Mechanics Evaluation of the Stability of Bridgehead Olefins Containing Medium Rings

  • 김장섭
    • Bulletin of the Korean Chemical Society
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    • v.18 no.5
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    • pp.488-495
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    • 1997
  • The stability of bridgehead olefins containing 8 and 10 membered rings has been investigated by the MMX molecular mechanics calculation together with the GMMX conformational searching program. A number of 'hyperstable' bridgehead olefins, which have negative olefin strain values, have been found from the calculated values of strain energy and olefin strain for the series of in- and out-bicyclo[n.3.3]alk-1-ene and in- and out-bicyclo[n.4.4]alk-1-ene (n=1 to 8). For the bridgehead olefins with 'out' topology, hyperstable olefins were found in the systems having cyclononene or larger rings. For the bridgehead olefins with 'in' topology, hyperstable olefins were found in the systems having cyclodecene or larger rings.

Molecular Characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from Goats in the Western Part of India by LSU of Nuclear Ribosomal DNA

  • Kumar, Ashwani;Chaudhary, Anshu;Verma, Chandni;Singh, Hridaya Shanker
    • Parasites, Hosts and Diseases
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    • v.52 no.6
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    • pp.701-705
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    • 2014
  • The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India.