Ferrochelatase seems to have a structurally conserved core region that is common to the enzyme from bacteria, plants and mammals. We propose that porphyrin binds in the identified cleft; this cleft also includes the metal-binding site of the enzyme. It is likely that the structure of the cleft region will have different conformations upon substrate binding and release.

L1 has a dual function as a ribosomal protein binding rRNA and as a translational repressor binding mRNA. The crystal structure of L1 from Thermus thermophilus has been determined at 1.85 angstroms resolution. The protein is composed of two domains with the N‐ and C‐termini in domain I. The eight N‐terminal residues are very flexible, as the quality of electron density map shows. Proteolysis experiments have shown that the N‐terminal tail is accessible and important for 23S rRNA binding. Most of the conserved amino acids are situated at the interface between the two domains. They probably form the specific RNA binding site of L1. Limited non‐covalent contacts between the domains indicate an unstable domain interaction in the present conformation. Domain flexibility and RNA binding by induced fit seems plausible.

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For some forty years the eye-tracking technology has facilitated the study of eye movement patterns for sighted people during reading and other visual activities. Today -a newly developed automatic finger tracking system makes it possible to reconstruct blind peopleÕs tactile reading in real time and to automatically analyze finger movements during Braille text reading and tactile picture recognition. In this case study, the very first automatic finger tracking system is presented together with results indicating how Braille readers can increase awareness of their own reading styles. This opens up for future Braille education to become more evidence-based and, at the same time, for a new research field: contrastive studies of language in its auditory, visual and tactile manifestations.

This paper examines the use of the Internet as experienced by people with significant mobility/physical impairments who are accustomed to using computers. The study is based on interviews and focuses on computer usage in everyday action and interaction. In many cases, the possibilities that the computer and Internet offer have meant not only important improvements in quality of life, but first-time occurrences of great personal significance. The analysis is phenomenographic, resulting in main categories and subcategories, illustrated primarily through direct quotations. The three main categories are independence, communication, and learning.