Penicillin-Binding Protein 2x of Streptococcus pneumoniae: The Mutation Ala707Asp Within the C-terminal PASTA2 Domain Leads to Destabilization.

Microb Drug Resist. 2014 Jun;20(3):250-7. doi: 10.1089/mdr.2014.0082. Epub 2014 May 19.

Penicillin-Binding Protein 2x of Streptococcus pneumoniae: The Mutation Ala707Asp Within the C-terminal PASTA2 Domain Leads to Destabilization.

Schweizer I1, Peters K, Stahlmann C, Hakenbeck R, Denapaite D.

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Abstract

Streptococcus pneumoniae penicillin-binding protein 2x (PBP2x) is an enzyme involved in the last stages of peptidoglycan assembly and essential for bacterial growth and survival. PBP2x localizes to the division site, a process that depends on its Penicillin-Binding Protein And Serine-Threonine-kinase Associated (PASTA) domains, which was previously demonstrated via GFP-PBP2x in living cells. During this study a mutant strain was isolated in which the GFP-PBP2x fusion protein did not localize at division sites and it contained reduced amounts of the full-length GFP-PBP2x. We now show that this defect is due to a point mutation within the C-terminal PASTA2 domain of PBP2x. The mutant protein was analyzed in detail in terms of beta-lactam binding, functionality, and localization in live cells. We demonstrate that the mutation affects the GFP-tagged PBP2x variant severely and renders it susceptible to the protease/chaperone HtrA.

PMID: 24841912 [PubMed - in process]