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Posttranslational modification of protein lysyl residues that change the net charge of the molecule may alter the protein conformation. Such modifications are of particular significance among lens proteins, because conformational changes are associated with the development of cataract. A previously unidentified acetylated form of aA-crystallin has been isolated from the water-soluble portion of human lenses. The aA-crystallins were fractionated by anion exchange HPLC into seven peaks, each containing more than one form of aA-crystallin. The previously reported deamidated and phosphorylated forms were identified by their molecular masses, determined by electrospray ionization mass spectrometry. In addition to these modifications, approximately 5% of aA-crystallin had a modification that decreased the charge by one and increased the molecular mass by 42 u. This modification, identified as acetylation, was located uniquely at Lys 70. Like any modification that alters the surface charge, acetylation may affect protein conformation and intermolecular interactions, thereby altering the solubility or chaperone properties of aA-crystallin. Acetylation of lysine 70 is potentially significant since it is located in a region that has been implicated in the chaperone activity of aA-crystallin. Keywords: acetylation; ion exchange; lens crystallins; mass spectrometryProper close-packing of the proteins in the eye lens is required for transparency. The a-crystallins, which comprise approximately 30% of the lens proteins, contribute to proper close packing through both their function as structural proteins and their chaperone-like activity in maintaining the solubility of other lens crystallins (Horwitz, 1992;Muchowski et al., 1997). Post-translational modifications that affect either of these functions may contribute to cataractogenesis. Because lysyl residues have a positive charge under physiological conditions, they are likely participants in ionic interactions required for close-packing. Modifications that alter the charge of lysyl groups may be expected to alter the close packing of crystallins in the lens. Modified lysyl residues and their effects on aggregation properties have been observed primarily with lens crystallins incubated in vitro with the modifying agents. Several in vivo modifications at lysyl resides have been implicated in the development of cataract, yet these modifications have been reported to be present at fewer than 1% of the lysines (Dunn et al., 1989;Dyer et al., 1991;Nagaraj et al., 1991) and the exact locations of the modifications have not been specified. We report an in vivo modification of human aA-crystallin, located only at Lys 70. This modification, which removes one positive charge of aA- crystallin and increases the molecular mass by 42 u, is present in approximately 5% of aA-crystallin molecules. ResultsThe water-soluble aA-crystallins of each lens were separated into seven peaks by anion exchange chromatography at pH 6.2, each containing more than one species. Figure 1 is a repre...

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Translation of the Bible or any other text unavoidably involves a determination about its meaning. There have been different views of meaning from ancient times up to the present, and a particularly Enlightenment and Modernist view is that the meaning of a text amounts to whatever the original author of the text intended it to be. This article analyzes the authorial-intent view of meaning in comparison with other models of literary and legal interpretation. Texts are anchors to interpretation but are subject to individualized interpretations. It is texts that are translated, not intentions. The challenge to the translator is to negotiate the meaning of a text and try to choose the most salient and appropriate interpretation as a basis for bringing the text to a new audience through translation.