Contact: Greg Lester
The Wistar Institute
Caption: Histone acetyltransferases (HATs) are enzymes that can epigenetically modify gene regulation. Just how they modify their targets depends on the shape they form. This ring structure is formed by two Rtt109 HATs (purple and gold) and two Vsp75 "chaperones" (blue and green), which are proteins that guide the enzymes to their target by, in part, dictating the size of the hole formed when they make a ring. As the HAT settles atop its target (a histone protein) the shape of the ring complex determines which part of the target gets modified. Other chaperones may help Rtt109 modify other parts of its target protein.
Credit: Ronen Marmostein, Ph.D./The Wistar Institute
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Related news release: How the hat fits: Structural biology study reveals shape of epigenetic enzyme complex