quorum sensing controls the luminescence of vibrio fischeri through the transcriptional activator luxr and the specific autoinducer signal produced by luxi. amino acid sequences of these two genes were analyzed using bioinformatics tools. luxi consists of 193 amino acids and appears to contain five α-helices and six ß-sheets when analyzed by sspro8. luxi belongs to the autoinducer synthetase fa...

We used 204 nm excitation UV resonance Raman (UVRR) spectroscopy to examine the role of side chain electrostatic interactions in determining the conformation of poly-L-lysine (PLL). We examined the pH and ionic strength dependence of the UVRR. The pH dependence of PLL UVRR spectra between pH 7.1 and 11.7 cannot be described by a two-state model but requires at least one additional state. The Am...

The cyclic-AMP binding domain (CBD) is the central regulatory unit of exchange proteins activated by cAMP (EPAC). The CBD maintains EPAC in a state of auto-inhibition in the absence of the allosteric effector, cAMP. When cAMP binds to the CBD such auto-inhibition is released, leading to EPAC activation. It has been shown that a key feature of such cAMP-dependent activation process is the partia...

The notion of a generalized helix in R3, a curve making a constant angle with a fixed direction, can be generalized to higher dimensions in many ways. In [7] the same definition is proposed but in R. In [4] the definition is more restrictive: the fixed direction makes a constant angle with all the vectors of the Frenet frame. It is easy to check that this definition only works in the odd dimens...