Proline residues properties

The most advanced PDF inhibitor to emerge thus far from this collaboration is LBM-415 (12) (also called NVP PDF-713 or VIC-104959), an V-formyl-V-hydroxylamine compound still containing a proline residue at P2. The activity, PK properties, and in vivo efficacy data of (12) were presented at the 14th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) (2004) and the structure of this... 

A different strategy for measuring protease activity is based on the property of xanthene dyes to form H-type dimers (see Sect. 6.2.3) when they are in close proximity. These dimers are accompanied with a characteristic quenching of their fluorescence and, particularly for rhodamines, with a blue shift in the absorption spectrum [121, 122]. The probe D-NorFES-D designed to measure activity of elastase in HL-60 cells consists of an undecapeptide derivatized with one tetramethylrhodamine dye on each side. The sequence contains proline residues to create a bent structure and bring the two fluoro-phores in close proximity. Intact D-NorFES-D shows 90% of its fluorescence quenched plus a blue shift of the absorption spectrum. After addition of the serine protease elastase, an increase in the fluorescence and a bathochromic shift of the absorption spectrum is observed, resulting in an increase in the emission ratio [80],... 

Cytochrome c possesses three phyllogenetically-conserved proline residues that are presumably involved in the correct folding of the protein to form the native structure. The effects of substitutions at one of these sites, Pro-71 (Fig. 4), on the equilibrium and kinetics of yeast iso-2-cytochrome c unfolding have been studied by Nall and co-workers through comparison of the properties of a Thr... 

These experiments lead us to consider another aspect of the configurational properties of proline-containing polypeptide chains which can be stated in the form of a question How many contiguous proline residues... 

The Ala-Pro-Tyr peptide is modelled with the N- and C-termini blocked with acetyl and methylamide groups respectively (see Figure 2). The type a and b dsproline-aromatic interactions are respectively characterised by strong chemical shift deviations on the a proton of the alanine residue and on the yl proton of the proline residue that are mainly due to the ring current effect of the tyrosine residue. This property will be used to identify the different crsproline-aromatic interactions. 

The activity of these biofunctional peptides is based on their inherent amino acid composition and sequence. The size of active sequences may vary from 2 to 20 amino acid residues, and many peptides are known to have multifunctional properties [89], e.g., peptides from the sequence 60-70 of P-casein show immunostimulatory, opioid, and angiotensin I converting enzyme (acetyl choline esterase [ACE]) -inhibitory activities. This sequence has been defined as a strategic zone [90,91]. The sequence is protected from proteolysis because of its high hydrophobicity and the presence of proline residues. Other examples of the multi-functionality of milk-derived peptides include the... 

Studies on the amino acid composition of ferritin could have permitted the prediction that the helical conformation of the molecule could be very high. Indeed, ferritin is low in valine, isoleucine, threonine, serine, and especially proline residues (1.2% of all amino acid), which would seriously disrupt helical regions. Studies of the optical rotary dispersion properties of ferritin established that the molecule is likely to contain 50% helical conformation. Once iron is removed from ferritin, the optical changes indicate further folding of the molecules, and although one can use ammonium sulfate and chromotographic analysis to separate ferritins with various iron content the changes in iron content do not affect the rotation properties of ferritin. 

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