Engineering the Substrate Specificity of ADP-Ribosyltransferases for Identifying Direct Protein Targets
摘要:
Adenosine diphosphate ribosyltransferases (ARTDs; ARTD1-17 in humans) are emerging as critical regulators of cell function in both normal physiology and disease. These enzymes transfer the ADP-ribose moiety from its substrate, nicotinamide adenine dinucleotide (NAD(+)), to amino acids of target proteins. The functional redundancy and overlapping target specificities among the 17 ARTDs in humans make the identification of direct targets of individual ARTD family members in a cellular context a formidable challenge. Here we describe the rational design of orthogonal NAD(+) analogue-engineered ARTD pairs for the identification of direct protein targets of individual ARTDs. Guided by initial inhibitor studies with nicotinamide analogues containing substituents at the C-5 position, we synthesized an orthogonal NAD(+) variant and found that it is used as a substrate for several engineered ARTDs (ARTD1, -2, and -6) but not their wild-type counterparts. Comparing the target profiles of ARTD1 (PARP1) and ARTD2 (PARP2) in nuclear extracts highlighted the semi-complementary, yet distinct, protein targeting. Using affinity purification followed by tandem mass spectrometry, we identified 42 direct ARTD1 targets and 301 direct ARTD2 targets. This represents a powerful new technique for identifying direct protein targets of individual ARTD family members, which will facilitate studies delineating the pathway from ARTD activation to a given cellular response.
使用光作为外部触发器来改变配体形状并因此改变其生物活性,可以以时空分辨率探测药理学相关系统。通过筛选最初设计为激酶抑制剂的化合物而产生的杂二苯乙烯先导化合物,作为光可切换沉默调节蛋白抑制剂设计的起点。由于原始的二苯乙烯类结构具有不利的光化学特性,因此将其改建为杂芳基二氮烯类似物。通过这种分子内偶氮化,分子的形状保持不变,而光开关能力得到提高。正如预期的那样,高度相似的化合物在其热力学稳定的拉伸 ( E ) 形式中表现出相似的活性。该异构体的辐照会引发异构化,形成具有弯曲几何形状的长寿命 ( Z ) 构型,从而导致端到端距离显着缩短。由此产生的亲和力变化旨在实现去乙酰化酶的体外实时光调制。