Strong DNA binding by covalently linked dimeric Lac headpiece: Evidence for the crucial role of the hinge helices

The combined structural and biochemical studies on Lac repressor bound to operator DNA have demonstrated the central role of the hinge helices in operator bending and the induction mechanism. We have constructed a covalently linked dimeric Lac-headpiece that binds DNA with four orders of magnitude higher affinity as compared with the monomeric form. This enabled a detailed biochemical and structural study of Lac binding to its cognate wild-type and selected DNA operators. The results indicate a profound contribution of hinge helices to the stability of the protein–DNA complex and highlight their central role in operator recognition. Furthermore, protein–DNA interactions in the minor groove appear to modulate hinge helix stability, thus accounting for affinity differences and protein-induced DNA bending among the various operator sites. Interestingly, the in vitro DNA-binding affinity of the reported dimeric Lac construct can de readily modulated by simple adjustment of redox conditions, thus rendering it a potential artificial gene regulator.

Lac Rweru region, Burundi, 1995, Defense Mapping Agency (DMA) Series Z724, Sheet 4876-II (Raster Image)

This layer is a georeferenced raster image of the United States Defense Mapping Agency (DMA) Series Z724, Burundi, 1:50,000 Topographic Line Map (TLM) Series sheet map entitled: Lac Rweru. Printed in: 1995. Covers portions of Lac Rweru region, Burundi. Sheet: 4876-II. Edition statement: Ed. 1 - DMA. The image inside the map neatline is georeferenced to the surface of the earth and fit to World Geodetic System (1984) coordinates. All map collar information is also available as part of the raster image. Burundi 1:50:000 Series Z724 maps are in English and French (legends also include Rundi). Each source map in the series is printed in color at a scale of 1:50,000. Series source sheets were published in 1994-1995 by the United States Defense Mapping Agency, Hydrographic/Topographic Center. The source map was scanned and georeferenced for Harvard University's Center for Geographic Analysis' AfricaMap project by East View Cartographic. Individual TLM sheets covering Burundi (40 sheets in total) were selected from the TLM worldwide series. DMA Topographic Line Map series maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 20 meters, with some sheets having supplemental meter contours, form lines, hachures, shading, and/or spot heights. Depths shown by bathymetric isolines. Please pay close attention to map collar information on projections, spheroid, compilation dates, legend information, and keys to grid numbering and other numbers which appear inside the neatline.

Voyages chez différentes nations sauvages de l'Amérique septentrionale : renfermant des détails curieux sur les moeurs, usages, cérémonies religieuses, le systême militaire, &c. des Cahnuagas, des indiens des Cinq et Six Nations, Mohawks, Connecedagas, Iroquois, &c. des indiens Chippeway, & autres sauvages de divers tribus; sur leurs langues, les pays qu'ils habitent, ainsi que sur le commerce de pelleteries & fourrures qui se fait chez le fleuve S. Laurent, le lac Ontario, &c. /

Es la traduciión francesa de la obra "Voyages and travels of an Indian interpreter and trader", cuya primera edición es de : London, 1791.

Lac Marianum seu Hymnus suauissimus B. Mariae Virginis honori dicatus /

Mode of access: Internet.

On the origin of the lac.

Caption title.

Mission Chari-Lac Tchad, 1902-1904. L'Afrique Centrale Française. Récit du voyage de la mission,

Mode of access: Internet.