Jung-Eun Shin L&S Sciences
Overexpression of protein Hfq causes adverse effects to small RNA-mRNA duplex formation
Can there be too much of a good thing in biochemical systems? We propose that in a system where one component interacts with two different substrates, there can be too much of the dual substrate-binding component such that the rate of reaction will begin to decrease. To test this hypothesis, we study a model regulation system: small noncoding RNA have been identified that work to tune mRNA expression. Hfq is a protein that aids in formation of a small RNA-mRNA duplex. Hfq is the dual substrate-binding component, and the sRNAs and mRNAs are the two substrates. The sRNA-mRNA duplex forms if one Hfq molecule acts on both the sRNA and the mRNA. In excess Hfq, all of the sRNAs and mRNAs each bind an Hfq protein, so a single Hfq molecule is unable to bind both sRNA and mRNA. This can be considered a flooding effect, where too much Hfq causes a decreased rate of reaction.