Crystallographic Structure of Phosphofructokinase-2 from Escherichia coli in Complex with Two ATP Molecules. Implications for Substrate Inhibition

Phosphofructokinase-1 and -2 (Pfk-1 and Pfk-2, respectively) from Escherichia coli belong to different homologous superfamilies. However, in spite of the lack of a common ancestor, they share the ability to catalyze the same reaction and are inhibited by the substrate MgATP. Pfk-2, an ATP-dependent 6-phosphofructokinase member of the ribokinase-like superfamily, is a homodimer of 66 kDa subunits whose oligomerization state is necessary for catalysis and stability. The presence of MgATP favors the tetrameric form of the enzyme. In this work, we describe the structure of Pfk-2 in its inhibited tetrameric form, with each subunit bound to two ATP molecules and two Mg ions. The present structure indicates that substrate inhibition occurs due to the sequential binding of two MgATP molecules per subunit, the first at the usual site occupied by the nucleotide in homologous enzymes and the second at the allosteric site, making a number of direct and Mg-mediated interactions with the first. Two configurations are observed for the second MgATP, one of which involves interactions with Tyr23 from the adjacent subunit in the dimer and the other making an unusual non-Watson-Crick base pairing with the adenine in the substrate ATP. The oligomeric state observed in the crystal is tetrameric, and some of the structural elements involved in the binding of the Substrate and allosteric ATPs are also participating in the dimer-dimer interface. This structure also provides the grounds to compare analogous features of the nonhomologous phosphofructokinases from E. coli. (C) 2008 Elsevier Ltd. All rights reserved.

Lansering av The Richard Juhlin Champagne Club Introducing The Richard Juhlin Champagne Club

Richard Juhlin är världens främste champagneexpert. Han har tillsammans med ett antal andra aktörer startat The Richard Juhlin Champagne Club. Det är en klubb för den totala champagne älskaren. De vill utveckla sin webbplats och därmed knyta an fler medlemmar till klubben. Detta arbete innebär att skapa en ny design, se över struktur och gränssnitt för sidan samt att bilder ska uppdateras och texter ska redigeras. En redesign av webbplatsen www.champagneclub.com har resulterat i ett luftigt och sofistikerat utseende med god läsbarhet. Webbplatsen är lättnavigerad och ger ett inbjudande intryck för besökaren. Webbplatsen ska hela tiden uppdateras och hållas aktuell med nyheter kring de tillhörande barerna, andra aktiviteter som medlemmar blir inbjudna till samt nya tastingnots som är The Rickard Juhlin Champagne Clubs specialitet. Dessa notes är gjorda av Richard Juhlin och fylls ständigt på allt eftersom att nya champagner provas och bedöms.

Looking for Richard e Shakespeare in love : Shakespeare pela ótica do cinema hollywoodiano pós-modernista

A presente dissertação aborda o diálogo intertextual interdisciplinar que os filmes cinematográficos Shakespeare in Love (John Madden, 1998) e Looking for Richard (Al Pacino,1996) estabelecem em relação ao conjunto da obra de William Shakespeare. A análise dos filmes demonstra que, tanto pela estruturação de suas narrativas quanto por suas posturas frente ao legado cultural shakespeariano e seu papel na cultura de massa contemporânea, tais filmes configuram-se como obras de arte pós-modernistas. Tendo por base abordagens culturais abrangentes do fenômeno pós-modernista, concluimos que Shakespeare in Love e Looking for Richard propõem um redimensionamento da obra canônica de Shakespeare e de seu legado cultural na contemporaneidade, recuperando seu forte apelo popular através do cinema de entretenimento hollywoodiano.