Solving AMPK

The enzyme AMP-activated protein kinase (AMPK) has been shown to be central to regulating several metabolic systems such as glucose uptake, oxidation of fatty acids, and insulin sensitivity, but the crystal structure of the mammalian enzyme remained elusive. Bing Xiao and others from the United Kingdom's National Institute for Medical Research used X-ray crystallography to map the structure of AMPK when bound to AMP and ATP, which the enzyme binds competitively,1 illuminating AMPK regulation.

"This is the first study to reveal the structural basis for AMP binding to mammalian AMPK," writes Anthony Means of the Duke University Medical Center on the Faculty of 1000 Web site. Means comments that Xiao's paper provides a hypothesis of how AMP affects AMPK activity. The enzyme consists of three protein subunits labeled α, β, and γ. This study suggests that when AMP binds to the γ subunit, the enzyme undergoes a conformational change that ...