Structural Studies of Geosmin Synthase, a Bifunctional Sesquiterpene Synthase with αα Domain Architecture That Catalyzes a Unique Cyclization–Fragmentation Reaction Sequence
- Univ. of Pennsylvania, Philadelphia, PA (United States). Roy and Diana Vagelos Labs.
- Univ. of Pennsylvania, Philadelphia, PA (United States). Roy and Diana Vagelos Labs.; Johns Hopkins Univ., Baltimore, MD (United States). School of Medicine
- SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
- Univ. of Pennsylvania, Philadelphia, PA (United States). Roy and Diana Vagelos Labs.; Christopher Newport Univ., Newport News, VA (United States)
- Univ. of Pennsylvania, Philadelphia, PA (United States). Roy and Diana Vagelos Labs.; Izmir Inst. of Technology (IYTE), Izmir (Turkey)
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Brown Univ., Providence, RI (United States)
- Univ. of Pennsylvania, Philadelphia, PA (United States). Roy and Diana Vagelos Labs.; Harvard Univ., Cambridge, MA (United States). Radcliffe Inst. for Advanced Study
Geosmin synthase from Streptomyces coelicolor (ScGS) catalyzes an unusual, metal-dependent terpenoid cyclization and fragmentation reaction sequence. Two distinct active sites are required for catalysis: the N-terminal domain catalyzes the ionization and cyclization of farnesyl diphosphate to form germacradienol and inorganic pyrophosphate (PPi), and the C-terminal domain catalyzes the protonation, cyclization, and fragmentation of germacradienol to form geosmin and acetone through a retro-Prins reaction. A unique αα domain architecture is predicted for ScGS based on amino acid sequence: each domain contains the metal-binding motifs typical of a class I terpenoid cyclase, and each domain requires Mg2+ for catalysis. In this paper, we report the X-ray crystal structure of the unliganded N-terminal domain of ScGS and the structure of its complex with three Mg2+ ions and alendronate. These structures highlight conformational changes required for active site closure and catalysis. Although neither full-length ScGS nor constructs of the C-terminal domain could be crystallized, homology models of the C-terminal domain were constructed on the basis of ~36% sequence identity with the N-terminal domain. Small-angle X-ray scattering experiments yield low-resolution molecular envelopes into which the N-terminal domain crystal structure and the C-terminal domain homology model were fit, suggesting possible αα domain architectures as frameworks for bifunctional catalysis.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; National Institutes of Health (NIH)
- Grant/Contract Number:
- AC02-06CH11357; AC02-05CH11231; P41 GM103403
- OSTI ID:
- 1229891
- Journal Information:
- Biochemistry, Vol. 54, Issue 48; ISSN 0006-2960
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
Crystal structure and functional analysis of large-terpene synthases belonging to a newly found subclass
|
journal | January 2018 |
Towards a comprehensive understanding of the structural dynamics of a bacterial diterpene synthase during catalysis
|
text | January 2018 |
Chimeric Terpene Synthases Possessing both Terpene Cyclization and Prenyltransfer Activities
|
journal | April 2018 |
Towards a comprehensive understanding of the structural dynamics of a bacterial diterpene synthase during catalysis
|
journal | September 2018 |
Correction to Structural and Chemical Biology of Terpenoid Cyclases
|
journal | December 2018 |
Similar Records
Structure and Function of Fusicoccadiene Synthase, a Hexameric Bifunctional Diterpene Synthase
Crystal structure of F95Q epi-isozizaene synthase, an engineered sesquiterpene cyclase that generates biofuel precursors β- and γ-curcumene