MF7000223 SurE, E112A/D230A mutant (Salmonella typhimurium) 4xh8 X-ray 3.56 Homodimer Salmonella typhimurium 26327371 Mathiharan YK, Savithri HS, Murthy MR Acta Crystallogr. D Biol. Crystallogr. 2015 Pt 9 71 1812-23 The survival protein SurE from Salmonella typhimurium (StSurE) is a dimeric protein that functions as a phosphatase. SurE dimers are formed by the swapping of a loop with a pair of β-strands and a C-terminal helix between two protomers. In a previous study, the Asp230 and His234 residues were mutated to Ala to abolish a hydrogen bond that was thought to be crucial for C-terminal helix swapping. These mutations led to functionally inactive and distorted dimers in which the two protomers were related by a rotation of 167°. New salt bridges involving Glu112 were observed in the dimeric interface of the H234A and D230A/H234A mutants. To explore the role of these salt bridges in the stability of the distorted structure, E112A, E112A/D230A, E112A/H234A, E112A/D230A/H234A, R179L/H180A/H234A and E112A/R179L/H180A/H234A mutants were constructed. X-ray crystal structures of the E112A, E112A/H234A and E112A/D230A mutants could be determined. The dimeric structures of the E112A and E112A/H234A mutants were similar to that of native SurE, while the E112A/D230A mutant had a residual rotation of 11° between the B chains upon superposition of the A chains of the mutant and native dimers. The native dimeric structure was nearly restored in the E112A/H234A mutant, suggesting that the new salt bridge observed in the H234A and D230A/H234A mutants was indeed responsible for the stability of their distorted structures. Catalytic activity was also restored in these mutants, implying that appropriate dimeric organization is necessary for the activity of SurE. GO:0008254 3'-nucleotidase activity GO:0008253 5'-nucleotidase activity GO:0004309 exopolyphosphatase activity GO:0046872 metal ion binding GO:0000166 nucleotide binding GO:0106411 XMP 5'-nucleosidase activity GO:0005737 cytoplasm 2 1 Homooligomeric enzymes Homodimeric enzymes All chains according to the most probable oligomerization state stored in PDBe were considered. A 5'/3'-nucleotidase SurE Salmonella typhimurium P66881 1 253 100% MRILLSNDDGVHAPGIQTLAKALREFADVQVVAPDRNRSGASNSLTLESSLRTFTFDNGDIAVQMGTPTDCVYLGVNALMRPRPDIVVSGINAGPNLGDDVIYSGTVAAAMEGRHLGFPALAVSLNGYQHYDTAAAVTCALLRGLSREPLRTGRILNVNVPDLPLAQVKGIRVTRCGSRHPADKVIPQEDPRGNTLYWIGPPGDKYDAGPDTDFAAVDEGYVSVTPLHVDLTAHSAHDVVSDWLDSVGVGTQW 253 secondary structure helix 27 38 secondary structure helix 81 92 secondary structure helix 111 115 secondary structure helix 118 124 secondary structure helix 144 162 secondary structure helix 226 234 secondary structure helix 250 261 secondary structure strand 16 19 secondary structure strand 42 48 secondary structure strand 66 69 secondary structure strand 75 78 secondary structure strand 103 107 secondary structure strand 135 140 secondary structure strand 170 175 secondary structure strand 184 187 secondary structure strand 192 193 secondary structure strand 199 203 secondary structure strand 209 213 secondary structure strand 219 221 secondary structure strand 235 239 pfam PF01975 Survival protein SurE 3 180 B 5'/3'-nucleotidase SurE Salmonella typhimurium P66881 1 253 100% MRILLSNDDGVHAPGIQTLAKALREFADVQVVAPDRNRSGASNSLTLESSLRTFTFDNGDIAVQMGTPTDCVYLGVNALMRPRPDIVVSGINAGPNLGDDVIYSGTVAAAMEGRHLGFPALAVSLNGYQHYDTAAAVTCALLRGLSREPLRTGRILNVNVPDLPLAQVKGIRVTRCGSRHPADKVIPQEDPRGNTLYWIGPPGDKYDAGPDTDFAAVDEGYVSVTPLHVDLTAHSAHDVVSDWLDSVGVGTQW 253 secondary structure helix 27 39 secondary structure helix 81 92 secondary structure helix 111 117 secondary structure helix 118 123 secondary structure helix 144 162 secondary structure helix 226 234 secondary structure helix 250 262 secondary structure strand 15 20 secondary structure strand 41 48 secondary structure strand 66 69 secondary structure strand 75 78 secondary structure strand 100 107 secondary structure strand 135 140 secondary structure strand 169 175 secondary structure strand 184 187 secondary structure strand 192 193 secondary structure strand 199 203 secondary structure strand 209 213 secondary structure strand 219 221 secondary structure strand 235 241 pfam PF01975 Survival protein SurE 3 180 Direct evidence The full structure participates in mutual synergistic folding. Survival protein SurE Two-state thermal unfolding (PMID:23409101). Domain-swapped dimer with extensive swap region and large dimer interface. Dimeric in solution (gel filtration, DLS). A N/A B N/A MF7000821 MF7000221 MF7000222 MF7000224 MF7000227 MF7000223 MF7000225 MF7000226