Q2. What is the importance of the geometric orientation of bioactive molecules?
given the specific tertiary structure of proteins, the geometric orientation of bioactive molecules is crucial to their ability to favourably interact with active and allosteric sites.
Q3. What is the role of marinopyrrole A in the treatment of cancer?
Marinopyrrole derivatives with a cyclic structure and sulphide substituents have proven to be promising inhibitors of the interactions between proapoptotic proteins, Bcl-xL and Mcl-1, and their target pro-survival protein, Bim.64, 65, 74 It was also found that marinopyrrole A may restore activity of the anticancer drug ABT-737 to resistant cancer cells.75
Q4. What is the common peptide in the ustiloxin family?
Alongside well-known vinca alkaloids, some naturally-occurring peptidic molecules elicit such inhibition, including the atropisomeric ustiloxin family of molecules, which target the α,β-tubulin dimer.
Q5. What was the first successful approach in the generation of ustiloxin D?
The first successful approach in the generation of ustiloxin D was a linear total synthesis consisting of 31 steps, with an 82% yield on average for each step.
Q6. What is the common method used to determine the half-lives of atropisome?
such half-lives are determined using chiral HPLC at low temperatures, to evaluate the configurational stability of an atropisomer against inversion, though computational calculation of rotational energy barriers is also an effective technique.
Q7. What is the main product of abyssomicin C?
In 2011, Gottardi et al treated cultures of V. maris AB-18-032 with 13C-labelled precursors and found that abyssomicin C is biosynthetically produced from five acetates, two propionates, and a glycolytic pathway metabolite.
Q8. What techniques were successful in the identification of point chirality in the atropisomeric?
vibrational circular dichroism (VCD) and vibrational absorption (VA) techniques were successful in the identification of point chirality in the atropisomeric cephalochromin.31
Q9. What is the common method of detecting atropenantiomers?
There are various ab initio methods which may be applied,15 though the most common of these relies on optimizing the structures of the two predicted atropenantiomers with a density functional theory (DFT), then applying a time-dependent (TD) perturbation to predict the vibrational or electronic transitions.
Q10. How many aromatic protons were found in the unnamed dimer?
78 Analysis of the 1H-NMR spectrum of the unnamed dimer revealed it to be asymmetric by the presence of two sets of peaks, resulting in a total of eleven aromatic protons.
Q11. How was the native atropisomer 5f obtained?
The final yield of the native (P) atropisomer 5f was 22% from the enantiopure biaryl thiolactone 8, and could be quantitatively converted to the (M) form by heating to 60 °C in neutral methanol.
Q12. What is the main difference between atropisomers and rotamers?
Unlike stereogenicity arising from point chirality, which may only be altered through the breaking and reformation of chemical bonds, the configuration of atropisomers is governed primarily by their thermodynamic environment.
Q13. What was the mechanism for the assignment of the major naturally occurring product?
It was in a study by Challis et al in 2010 that NOESY correlations of the HCl salts of extracted streptorubin B allowed for assignment of the major naturally occurring product as being the anticonfiguration with regards to the positioning of the C7ʹ n-butyl group relative to rings A and B, with the syn configuration only present in minor amounts.