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High‐resolution structures of both ribosomal subunits revealed that most stages of protein biosynthesis, including decoding of genetic information, are navigated and controlled by the elaborate ribosomal architectural‐design. Remote interactions govern accurate substrate alignment within a flexible active‐site pocket [peptidyl transferase center (PTC)], and spatial considerations, due mainly to a universal mobile nucleotide, U2585, ensure proper chirality by interfering with D‐amino‐acids incorporation. tRNA translocation involves two correlated motions: overall mRNA/tRNA (messenger and transfer RNA) shift, and a rotation of the tRNA single‐stranded aminoacylated‐3′ end around the bond connecting it with the tRNA helical‐regions. This bond coincides with an axis passing through a sizable symmetry‐related region, identified around the PTC in all large‐subunit crystal structures. Propelled by a bulged universal nucleotide, A2602, positioned at the two‐fold symmetry axis, and guided by a ribosomal‐RNA scaffold along an exact pattern, the rotatory motion results in stereochemistry optimal for peptide‐bond formation and in geometry ensuring nascent proteins entrance into their exit tunnel. Hence, confirming that ribosomes contribute positional rather than chemical catalysis, and that peptide bond formation is concurrent with A‐ to P‐site tRNA passage. Connecting between the PTC, the decoding center, the tRNA entrance and exit points, the symmetry‐related region can transfer intra‐ribosomal signals between remote functional locations, guaranteeing smooth processivity of amino acids polymerization. Ribosomal proteins are involved in accurate substrate placement (L16), discrimination and signal transmission (L22) and protein biosynthesis regulation (CTC). Residing on the exit tunnel walls near its entrance, and stretching to its opening, protein‐L22 can mediate ribosome response to cellular regulatory signals, since it can swing across the tunnel, causing gating and elongation arrest. Each of the protein CTC domains has a defined task. The N‐terminal domain stabilizes the intersubunit‐bridge confining the A‐site‐tRNA entrance. The middle domain protects the bridge conformation at elevated temperatures. The C‐terminal domain can undergo substantial conformational rearrangements upon substrate binding, indicating CTC participation in biosynthesis‐control under stressful conditions. Copyright © 2004 John Wiley & Sons, Ltd.

Nascent proteins emerge out of ribosomes through an exit tunnel, which was assumed to be a firmly built passive path. Recent biochemical results, however, indicate that the tunnel plays an active role in sequence-specific gating of nascent chains and in responding to cellular signals. Consistently, modulation of the tunnel shape, caused by the binding of the semi-synthetic macrolide troleandomycin to the large ribosomal subunit from Deinococcus radiodurans, was revealed crystallographically. The results provide insights into the tunnel dynamics at high resolution. Here we show that, in addition to the typical steric blockage of the ribosomal tunnel by macrolides, troleandomycin induces a conformational rearrangement in a wall constituent, protein L22, flipping the tip of its highly conserved β-hairpin across the tunnel. On the basis of mutations that alleviate elongation arrest, the tunnel motion could be correlated with sequence discrimination and gating, suggesting that specific arrest motifs within nascent chain sequences may induce a similar gating mechanism.

A major percentage of the violence against women includes sexual violence. Sexual assault is a frequently committed, mostly underreported and increasingly common violent crime. Sexual assault accounts for approximately 7% of all violent crimes.1It has a clear and measurable impact on the mental and physical health of the survivors of these crimes. These profound consequences make rape and sexual assault major public health issues.

This retrospective study investigated by mailed questionnaire all couples (n = 86) who completed in vitro fertilization (IVF) treatment and did not become pregnant. Fifty-two percent of the questionnaires were returned. The effect of IVF failure on couples' marital relationship, sexual functioning, and lifestyle was significant. Sixty-six percent of the women and 40% of the men reported depression following IVF failure, the severity of depression decreasing over time. Ninety-four percent of the women and 64% of the men reported somatic and psychological symptoms of depression and anxiety. The stress of undergoing IVF was compared to other stressful life events. Coping mechanisms and support systems are described. Suggestions for helping couples cope with IVF failure are discussed.

To report an unusual presentation of a patient with unicornuate uterus and a noncommunicating functional rudimentary horn and discuss related patient management issues.