Details

Autor(en) / Beteiligte

• Morgan, Jacob L W
• McNamara, Joshua T
• Zimmer, Jochen

Titel

Mechanism of activation of bacterial cellulose synthase by cyclic di-GMP

Ist Teil von

• Nature structural & molecular biology, 2014-05, Vol.21 (5), p.489-496

Ort / Verlag

United States

Erscheinungsjahr

2014

Quelle

MEDLINE

Beschreibungen/Notizen

• The bacterial signaling molecule cyclic di-GMP (c-di-GMP) stimulates the synthesis of bacterial cellulose, which is frequently found in biofilms. Bacterial cellulose is synthesized and translocated across the inner membrane by a complex of cellulose synthase BcsA and BcsB subunits. Here we present crystal structures of the c-di-GMP-activated BcsA-BcsB complex. The structures reveal that c-di-GMP releases an autoinhibited state of the enzyme by breaking a salt bridge that otherwise tethers a conserved gating loop that controls access to and substrate coordination at the active site. Disrupting the salt bridge by mutagenesis generates a constitutively active cellulose synthase. Additionally, the c-di-GMP-activated BcsA-BcsB complex contains a nascent cellulose polymer whose terminal glucose unit rests at a new location above BcsA's active site and is positioned for catalysis. Our mechanistic insights indicate how c-di-GMP allosterically modulates enzymatic functions.