Inhibitor binding increases the mechanical stability of staphylococcal nuclease.

Staphylococcal nuclease (SNase) catalyzes the hydrolysis of DNA and RNA in a calcium-dependent fashion. We used AFM-based single-molecule force spectroscopy to investigate the mechanical stability of SNase alone and in its complex with an SNase inhibitor, deoxythymidine 3',5'-bisphosphate. We found that the enzyme unfolds in an all-or-none fashion at ∼26 pN. Upon binding to the inhibitor, the mechanical unfolding forces of the enzyme-inhibitor complex increase to ∼50 pN. This inhibitor-induced increase in the mechanical stability of the enzyme is consistent with the increased thermodynamical stability of the complex over that of SNase. Because of its strong mechanical response to inhibitor binding, SNase, a model protein folding system, offers a unique opportunity for studying the relationship between enzyme mechanics and catalysis.

Full Text

Duke Authors

Cited Authors

  • Wang, CC; Tsong, TY; Hsu, YH; Marszalek, PE

Published Date

  • February 16, 2011

Published In

Volume / Issue

  • 100 / 4

Start / End Page

  • 1094 - 1099

PubMed ID

  • 21320455

Electronic International Standard Serial Number (EISSN)

  • 1542-0086

Digital Object Identifier (DOI)

  • 10.1016/j.bpj.2011.01.011

Language

  • eng

Citation Source

  • PubMed