3VGU:
reference: A structural mechanism for dimeric to tetrameric oligomer conversion in Halomonas sp. nucleoside diphosphate kinase., Arai S, Yonezawa Y, Okazaki N, Matsumoto F, Tamada T, Tokunaga H, Ishibashi M, Blaber M, Tokunaga M, Kuroki R, Protein Sci. 2012 Apr;21(4):498-510. doi: 10.1002/pro.2032. Epub 2012 Mar 9. PMID: 22275000

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