Document Detail

Real-time sensing and discrimination of single chemicals using the channel of phi29 DNA packaging nanomotor.
MedLine Citation:
PMID:  22458779     Owner:  NLM     Status:  MEDLINE    
A highly sensitive and reliable method to sense and identify a single chemical at extremely low concentrations and high contamination is important for environmental surveillance, homeland security, athlete drug monitoring, toxin/drug screening, and earlier disease diagnosis. This article reports a method for precise detection of single chemicals. The hub of the bacteriophage phi29 DNA packaging motor is a connector consisting of 12 protein subunits encircled into a 3.6 nm channel as a path for dsDNA to enter during packaging and to exit during infection. The connector has previously been inserted into a lipid bilayer to serve as a membrane-embedded channel. Herein we report the modification of the phi29 channel to develop a class of sensors to detect single chemicals. The lysine-234 of each protein subunit was mutated to cysteine, generating 12-SH ring lining the channel wall. Chemicals passing through this robust channel and interactions with the SH group generated extremely reliable, precise, and sensitive current signatures as revealed by single channel conductance assays. Ethane (57 Da), thymine (167 Da), and benzene (105 Da) with reactive thioester moieties were clearly discriminated upon interaction with the available set of cysteine residues. The covalent attachment of each analyte induced discrete stepwise blockage in current signature with a corresponding decrease in conductance due to the physical blocking of the channel. Transient binding of the chemicals also produced characteristic fingerprints that were deduced from the unique blockage amplitude and pattern of the signals. This study shows that the phi29 connector can be used to sense chemicals with reactive thioesters or maleimide using single channel conduction assays based on their distinct fingerprints. The results demonstrated that this channel system could be further developed into very sensitive sensing devices.
Farzin Haque; Jennifer Lunn; Huaming Fang; David Smithrud; Peixuan Guo
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2012-04-09
Journal Detail:
Title:  ACS nano     Volume:  6     ISSN:  1936-086X     ISO Abbreviation:  ACS Nano     Publication Date:  2012 Apr 
Date Detail:
Created Date:  2012-04-25     Completed Date:  2012-08-27     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  101313589     Medline TA:  ACS Nano     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3251-61     Citation Subset:  IM    
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MeSH Terms
Bacillus Phages / genetics*,  metabolism*
Benzene / analysis,  chemistry,  pharmacology
Biosensing Techniques / methods*
DNA Packaging* / drug effects
DNA, Viral / chemistry,  genetics*
Ethane / analysis,  pharmacology
Maleimides / analysis,  pharmacology
Models, Molecular
Nucleic Acid Conformation
Protein Conformation
Thymine / analysis,  pharmacology
Time Factors
Viral Proteins / chemistry,  genetics,  metabolism*
Grant Support
Reg. No./Substance:
0/DNA, Viral; 0/Maleimides; 0/Viral Proteins; 541-59-3/maleimide; J64922108F/Benzene; K848JZ4886/Cysteine; L99N5N533T/Ethane; QR26YLT7LT/Thymine

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