CBCHFX 12 (6) 813–972 (2011) · ISSN 1439-4227 · Vol. 12 · No. 6 · April 11, 2011 D55712

6/2011

www.chembiochem.org

Review: Strategies and Perspectives in Ion-Channel Engineering

(U. Koert)

Highlight: Hunting and Trapping Post-translational

Cysteine Modifications in Proteins and Enzymes

(C. Jacob)

A Journal of

Cover Picture

Irene Mart�n, Meritxell Teixid�*, and Ernest Giralt *

The cover picture shows a rocket representing the anionic cell-penetrating peptide(CPP) SAP(E) reported by E. Giralt, M. Teixid� and I. Mart�n on p. 896 ff. The “moon” is aconfocal microscopy image of HeLa cells after 3 hours of coincubation with CF-SAP andRd-SAP(E). To the best of our knowledge, SAP(E) is one of the first anionic CPPs to bedescribed. It adopts a polyproline II secondary structure in aqueous buffer and self-as-sembles to form aggregated structures able to internalize different cell lines withalmost no toxic effects. The internalization mechanism proposed for SAP(E) is clathrin-independent. Much can be achieved from a negatively charged CPP, for example, thespectrum of possible cargoes increases enormously. Positively charged cargoes couldnow be added to the list of molecules with the capacity to be delivered by these prom-ising vectors. Illustration made with the valuable help of Jos� Alberto Santos.