4KA9:
reference: Random single amino acid deletion sampling unveils structural tolerance and the benefits of helical registry shift on GFP folding and structure., Arpino JA, Reddington SC, Halliwell LM, Rizkallah PJ, Jones DD, Structure. 2014 Jun 10;22(6):889-98. doi: 10.1016/j.str.2014.03.014. Epub 2014, May 22. PMID: 24856363

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