Mulks M H, Plaut A G, Feldman H A, Frangione B
J Exp Med. 1980 Nov 1;152(5):1442-7. doi: 10.1084/jem.152.5.1442.
Strains of Neisseria meningitidis produce two distinct extracellular IgA proteases that cleave the human IgA1 heavy chain at different points within the hinge region. Type 1 protease cleaves the prolyl-seryl peptide bond at position 237-238; type type 2 protease cleaves the prolyl-threonyl bond two residues amino terminal to that bond attacked by type 1 enzyme. Each meningococcal isolate elaborates only one of these two enzymes, and the type of protease produced correlates with certain serogroups: group A yielding only type 1, and groups X and Y only type 2 enzyme. In addition, analysis of amino acid sequences of human alpha-chain proteins reveals that the repeating octapeptide characteristic of the IgA1 hinge region is actually triplicated.
脑膜炎奈瑟菌菌株产生两种不同的细胞外IgA蛋白酶，它们在铰链区内的不同位点切割人IgA1重链。1型蛋白酶切割237 - 238位的脯氨酰 - 丝氨酰肽键；2型蛋白酶切割的脯氨酰 - 苏氨酰键位于1型酶攻击的键的氨基末端两个残基处。每个脑膜炎球菌分离株仅产生这两种酶中的一种，所产生的蛋白酶类型与某些血清群相关：A群仅产生1型，X群和Y群仅产生2型酶。此外，对人α链蛋白氨基酸序列的分析表明，IgA1铰链区特有的重复八肽实际上是三倍重复的。
