4JNZ:
reference: Involvement of the beta3-alpha3 loop of the proline dehydrogenase domain in allosteric regulation of membrane association of proline utilization A., Zhu W, Haile AM, Singh RK, Larson JD, Smithen D, Chan JY, Tanner JJ, Becker DF, Biochemistry. 2013 Jul 2;52(26):4482-91. doi: 10.1021/bi400396g. Epub 2013 Jun, 19. PMID: 23713611

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