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The authors recently investigated Heck coupling reactions of vinyl glycinol 9 with different aryl halides. It was noted in the new study that the previously reported signs of the optical rotations of compounds 12a and 12f are wrong and must be corrected as follows: (S)-[1-hydroxymethyl-3-(6-methoxy-napthalen-2-yl)-propyl]-carbamic acid 9H-fluoren-9-ylmethylester 12a: [a] 20 D = + + 10.48 (c = 0.5, DMF) instead of À10.58 and (S)-(3-anthracen-9-yl-1-hydroxymethyl-propyl)-carbamic acid 9H-fluoren-9-ylmethylester 12f: [a] 20 D = + + 30.58 (c = 0.5, DMF) instead of À30.78. The authors apologize for any inconvenience caused by these errors.

The 27-mer peptide CP1B-w1-27x derived from exon 1B of calpastatin stands out among the known inhibitors for m-and m-calpain due to its high potency and selectivity.By systematical truncation, a 20-mer peptide, CP1B-w4-23x, was identified as the core sequence required to maintain the affinity/selectivity profile of CP1B-w1-27x. Starting with this peptide, the turn-like region Glu 10 (i)-Leu 11 (iq1)-Gly 12 (iq2)-Lys 13 (iq3) was investigated. Sequence alignment of subdomains 1B, 2B, 3B and 4B from different mammalians revealed that the amino acid residues in position iq1 and iq2 are almost invariably flanked by oppositely charged residues, pointing towards a turn-like conformation stabilized by salt bridge/H-bond interaction. Accordingly, using different combinations of acidic and basic residues in position i and iq3, a series of conformationally constrained variants of CP1B-w4-23x were synthesized by macrolactamization utilizing the side chain functionalities of these residues. With the combination of Glu(i)/Dab(iq3), the maximum of conformational rigidity without substantial loss in affinity/selectivity was reached. These results clearly demonstrate that the linear peptide chain corresponding to subdomain 1B reverses its direction in the region Glu 10 -Lys 13 upon binding to m-calpain, and thereby adopts a loop-like rather than a tight turn conformation at this site.

The light-driven disassembly process of amyloid-like structures formed by azobenzene model peptides is studied by time-resolved mid-IR spectroscopy from nanoseconds to minutes. The investigated peptide consists of two amino acid strands connected by the azobenzene switch. The peptides aggregate to amyloid-like structures when the azobenzene chromophore is in the trans-conformation. Illumination, resulting in a trans-to cis-isomerization of the azobenzene, leads to disaggregation of the aggregated structures. After optical excitation and isomerization of the azobenzene, one finds absorption changes which recover to a large extent on the time scale of few nanoseconds. These early absorption transients are assigned to the relaxation of vibrational excess energy (heat) or to structural rearrangements of isomerized azobenzene and the aggregated surroundings. It is only on the time scale of minutes that spectral signatures appear which are characteristic for the disassembly of the aggregated structure.

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