Milner-White E J
Biochim Biophys Acta. 1987 Jan 30;911(2):261-5. doi: 10.1016/0167-4838(87)90017-3.
Beta-bulges have been described as common irregularities in antiparallel beta-sheets. The two commonest kinds are described as 'classic' and 'G1'. The G1-type is often observed to occur at the loop end of beta-hairpins. I confirm this but also find that the characteristic G1 beta-bulge features (hydrogen bonds and dihedral angles) are found, in some loops, in the absence of any adjacent antiparallel beta-hairpin, so that the beta-bulge is effectively acting as a new sort of turn. Also I show that G1 beta-bulge loops occur in a number of different structural forms, some of which have not been described in detail before. G1 beta-bulge loops are common features; on average, a half of all proteins have one.
β-凸起被描述为反平行β-折叠中常见的不规则结构。最常见的两种类型被称为“经典型”和“G1型”。人们经常观察到G1型出现在β-发夹的环端。我证实了这一点，但也发现，在一些环中，即使没有任何相邻的反平行β-发夹，也能发现典型的G1β-凸起特征（氢键和二面角），因此β-凸起实际上起到了一种新型转角的作用。此外，我还表明，G1β-凸起环以多种不同的结构形式出现，其中一些以前尚未详细描述过。G1β-凸起环是常见特征；平均而言，所有蛋白质中有一半含有一个。
