Protein transport events occurring at the endoplasmic reticulum (ER) of eukaryotic cells and the cytoplasmic membrane of prokaryotic organisms share many similarities. Resident proteins of both membranes span the lipid bilayer once or several times by a-helical stretches and their integration is usually mediated by uncleaved signal-anchor sequences. Proteins that are translocated across either membrane, collectively also termed secretory proteins, harbour cleavable N-terminal signal sequences. Prokaryotic and eukaryotic signal sequences have the same modular structure and are functionally exchangeable. Integration of membrane proteins and translocation of secretory proteins basically occur at the same sites (pores) within each membrane. In both types of membranes, these pores are c- posed of homologous components forming the Sec translocons. Parts of the Sec trans- cons are found populated by ribosomes, the membrane-bound ribosomes. Bacterial m- brane and eukaryotic secretory proteins are targeted to the Sec translocons by the same molecular mechanism involving signal recognition particle (SRP) and its receptor (SRP - ceptor, SR). Structure and assembly of the SRP The functional core of SRP The functional core of this ribonucleoprotein complex consists of the signal sequence binding subunit (SRP54 in eukaryotes and Ffh in prokaryotes) and the SRP RNA molecule (see Fig. 1). This core is conserved in all organisms, with the intriguing exception of chloroplasts, where the SRP lacks the RNA subunit.

Protein transport events occurring at the endoplasmic reticulum (ER) of eukaryotic cells and the cytoplasmic membrane of prokaryotic organisms share many similarities. Resident proteins of both membranes span the lipid bilayer once or several times by a-helical stretches and their integration is usually mediated by uncleaved signal-anchor sequences. Proteins that are translocated across either membrane, collectively also termed secretory proteins, harbour cleavable N-terminal signal sequences. Prokaryotic and eukaryotic signal sequences have the same modular structure and are functionally exchangeable. Integration of membrane proteins and translocation of secretory proteins basically occur at the same sites (pores) within each membrane. In both types of membranes, these pores are c- posed of homologous components forming the Sec translocons. Parts of the Sec trans- cons are found populated by ribosomes, the membrane-bound ribosomes. Bacterial m- brane and eukaryotic secretory proteins are targeted to the Sec translocons by the same molecular mechanism involving signal recognition particle (SRP) and its receptor (SRP - ceptor, SR). Structure and assembly of the SRP The functional core of SRP The functional core of this ribonucleoprotein complex consists of the signal sequence binding subunit (SRP54 in eukaryotes and Ffh in prokaryotes) and the SRP RNA molecule (see Fig. 1). This core is conserved in all organisms, with the intriguing exception of chloroplasts, where the SRP lacks the RNA subunit.

Das Kompendium ist als Arbeitsbuch fur die tagliche Praxis des Radiologen, Unfallchirurgen, Orthopaden und Traumatologen gedacht. Eine rasche Orientierung ermoeglichen - die straffe, tief gestaffelte Gliederung, - Checklisten fur die systematische Bildanalyse, - synoptische Befunddarstellungen in Skizzen, - Tabellen und UEbersichten. Abgedeckt ist das gesamte Spektrum der traumatologischen Roentgendiagnostik inkl. Schadelhirntrauma, Verletzungen des Koerperstamms sowie roentgendiagnostisch erfassbarer Sportverletzungen. Auf den Abdruck von Roentgenbildern wurde verzichtet, da Fallbeispiele, im Gegensatz zu Skizzen, immer nur einen Teil der moeglichen Befunde wiedergeben koennen. Dafur sind auf der beiliegenden CD-Rom Roentgenaufnahmen abgespeichert und in eine interaktiv gefuhrte Bildanalyse eingebunden.