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. Author manuscript; available in PMC: 2019 Jul 22.
Published in final edited form as: Biol Chem. 2010 Jul;391(7):771–776. doi: 10.1515/BC.2010.078

Figure 2.

Figure 2

The proposed antigenic region in SepSecS or SLA/LP.

(A) The putative antigenic region of SepSecS is located near the active site of the enzyme (arrow). This region interacts with the tip of the acceptor arm of tRNASec and is crucial for tRNA recognition. The catalytic dimer of SepSecS is in shades of blue, the non-catalytic dimer is colored in shades of pink, two molecules of tRNASec are green, and the antigenic region is orange and demarcated with a box. (B) A close-up view of the interactions at the enzyme-tRNA interface. Residues from helices α14 and α15 interact with the tip of tRNASec. The helix α14 residues interact with the discriminator base G73: Arg398 forms hydrogen bonds with the Hoogsteen face of G73, whereas Thr397 stabilizes this interaction. The C-terminal helix α15 interacts with the tRNA backbone and with the 5′ phosphate. Arg453 and Arg456 are within hydrogen bonding distance from the 5′ phosphate, whereas Lys463 interacts with the non-bridging oxygens of C69 and G70.