Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 7

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

Fold recognition insights into function of herpes ICP4 protein

100%
Wyrwicz L. S., Rychlewski L.
|
2007
|
vol. 54
|
issue 3
551-559
EN
ICP4 is an important factor regulating the life cycle of HSV1. This conserved protein has several molecular functions, including activation of expression of viral late gene transcripts and inhibition of immediate early genes. Although ICP4 and its Alphaherpesvirinae homologs (eg.: IE62 of VZV) have been subjects of various molecular studies, a complete view of their molecular function is lacking. Here we present the results of fold recognition and molecular modelling of ICP4 functional domains. The performed state-of-the-art bioinformatic fold recognition analysis identified a dual helix-turn-helix motif as a binding module of repressor activities (so called region 2 domain). The mapping of distant homology identified that a segment responsible for activation of late gene promoters (region 4) exhibits folding of uracil DNA glycosylase (UDG), but seems to be a non-functional homolog of UDG. Potential implications of the results are discussed.
2
Content available remote

Cytomegalovirus immediate early gene UL37 encodes a novel MHC-like protein

100%
Wyrwicz L. S., Rychlewski L.
|
2008
|
vol. 55
|
issue 1
67-74
EN
The cytomegalovirus (CMV) genome encodes four clusters of genes expressed immediately after infection - i.e.: UL36-38, UL122-123, TRS1-IRS1, and US3. The general function of these genes is associated with inhibition of cellular mechanisms of antiviral response. Although several biological processes have been mapped onto specific gene products, the knowledge of the molecular mechanism of their activity remains fragmentary. Here, we report the application of protein structure prediction methods in assigning the function to a glycosylated domain encoded by UL37 of CMV (gpUL37, UL37x3). The discerned similarity clearly points out that this domain represents a novel type of a major histocompatibility complex (MHC)-like protein, and consequently may play a central role in an additional mechanism of escape from antiviral response.
3
Content available remote

Comparison of proteins based on segments structural similarity.

81%
Plewczynski D., Pas J., von Grotthuss M., Rychlewski L.
|
|
vol. 51
|
issue 1
161-172
EN
We present here a simple method for fast and accurate comparison of proteins using their structures. The algorithm is based on structural alignment of segments of Ca chains (with size of 99 or 199 residues). The method is optimized in terms of speed and accuracy. We test it on 97 representative proteins with the similarity measure based on the SCOP classification. We compare our algorithm with the LGscore2 automatic method. Our method has the same accuracy as the LGscore2 algorithm with much faster processing of the whole test set, which is promising. A second test is done using the ToolShop structure prediction evaluation program and shows that our tool is on average slightly less sensitive than the DALI server. Both algorithms give a similar number of correct models, however, the final alignment quality is better in the case of DALI. Our method was implemented under the name 3D-Hit as a web server at http://3dhit.bioinfo.pl/ free for academic use, with a weekly updated database containing a set of 5000 structures from the Protein Data Bank with non-homologous sequences.
4
Content available remote

Homologues of HSV-1 nuclear egress factor UL34 are potential phosphoinositide-binding proteins

81%
Wyrwicz L. S., Koczyk G., Rychlewski L.
|
2008
|
vol. 55
|
issue 1
207-213
EN
During the herpesvirus replication cycle, viral transcription, DNA replication, formation of capsids and DNA packaging occur in the nucleus. The subsequent nuclear egress of newly synthesized nucleocapsids is performed by budding of the inner leaflet of the nuclear membrane, which creates the primary envelope. Although products of two genes conserved throughout the Herpesviridae family (HSV-1 UL34 and UL31) have previously been shown to be involved in the execution of this process, the molecular basis of their activity is not clear. Here we present results of protein structure prediction for the conserved domain of UL34. The applied methodology suggests that this protein adopts a pleckstrin homology (PH) fold to perform its function. A detailed inspection of the ligand binding site strongly supports the hypothesis that UL34 orthologs can recognize phosphoinositides. Since previous works suggest that alterations of UL34 gene product result in a drastic impairment of primary envelopment of HSV-1 and trapping of capsids in the nucleus, the presented data may lead to the development of novel anti-herpetic therapeutic strategies where analogs of phosphoinositides are administered.
5
Content available remote

Prediction of signal peptides in protein sequences by neural networks

81%
Plewczynski D., Slabinski L., Ginalski K., Rychlewski L.
|
2008
|
vol. 55
|
issue 2
261-267
EN
We present here a neural network-based method for detection of signal peptides (abbreviation used: SP) in proteins. The method is trained on sequences of known signal peptides extracted from the Swiss-Prot protein database and is able to work separately on prokaryotic and eukaryotic proteins. A query protein is dissected into overlapping short sequence fragments, and then each fragment is analyzed with respect to the probability of it being a signal peptide and containing a cleavage site. While the accuracy of the method is comparable to that of other existing prediction tools, it provides a significantly higher speed and portability. The accuracy of cleavage site prediction reaches 73% on heterogeneous source data that contains both prokaryotic and eukaryotic sequences while the accuracy of discrimination between signal peptides and non-signal peptides is above 93% for any source dataset. As a consequence, the method can be easily applied to genome-wide datasets. The software can be downloaded freely from http://rpsp.bioinfo.pl/RPSP.tar.gz.
6
Content available remote

Unexpected domain composition of MACC1 links MET signaling and apoptosis

81%
Kokoszyńska K., Kryński J., Rychlewski L., Wyrwicz L. S.
|
|
issue 2
317-324
EN
Colorectal cancer, one of the most challenging malignancies, still has a limited number of recognized prognostic and predictive markers indicating appropriate treatment. MACC1 (metastasis-associated in colon cancer-1), a novel regulator of tumor growth and metastasis has recently been identified as an important prognostic factor of metastatic disease in colorectal cancer. The mechanism of MACC1 activity remains undetermined. Here we apply a combination of fold recognition and homology modeling algorithms to draft MACC1 function. The applied methods revealed that the MACC1 protein consists of four domains: ZU5, SH3, and two C-terminal death domains (DD). Previously a similar domain architecture (ZU5-DD) was observed in other proteins, involved mainly in signal transduction and apoptosis regulation. Based on the specific aspects of the closest homologues' biology functional hypotheses on MACC1 are proposed. A broad range of bioinformatic analyzes indicates that MACC1, besides its involvement in signal transduction from the MET receptor, links MET signaling and apoptosis.
7
Content available remote

A common cis-element in promoters of protein synthesis and cell cycle genes

71%
Wyrwicz L. S., Gaj P., Hoffmann M., Rychlewski L., Ostrowski J.
|
EN
Gene promoters contain several classes of functional sequence elements (cis elements) recognized by protein agents, e.g. transcription factors and essential components of the transcription machinery. Here we describe a common DNA regulatory element (tandem TCTCGCGAGA motif) of human TATA-less promoters. A combination of bioinformatic and experimental methodology suggests that the element can be critical for expression of genes involved in enhanced protein synthesis and the G1/S transition in the cell cycle. The motif was identified in a substantial fraction of promoters of cell cycle genes, like cyclins (CCNC, CCNG1), as well as transcription regulators (TAF7, TAF13, KLF7, NCOA2), chromatin structure modulators (HDAC2, TAF6L), translation initiation factors (EIF5, EIF2S1, EIF4G2, EIF3S8, EIF4) and previously reported 18 ribosomal protein genes. Since the motif can define a subset of promoters with a distinct mechanism of activation involved in regulation of expression of about 5% of human genes, further investigation of this regulatory element is an emerging task.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.