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Biophysical Characterization of Acyl Carrier Protein Domains from a Polyunsaturated Fatty Acid Synthase
Author(s) -
Rodriguez Uldaeliz Trujillo,
Oyola-Robles Delise,
Arold Stefan,
De Melo Fernando Alves,
Ladbury John E.,
Vazquez Edwin,
Vega Irving E.,
Baerga-Ortiz Abel
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.552.2
Subject(s) - microscale thermophoresis , small angle x ray scattering , tandem , fatty acid synthase , chemistry , acyl carrier protein , biosynthesis , circular dichroism , biochemistry , fatty acid , tandem repeat , atp synthase , polyunsaturated fatty acid , stereochemistry , enzyme , gene , scattering , physics , materials science , genome , optics , composite material
Acyl carrier protein (ACP) is a highly conserved protein domain that plays a key role in the biosynthesis of fatty acids and polyketides. The polyunsaturated fatty acid synthase complex from deep‐sea bacteria contains a total of five ACP domains in tandem. No satisfying explanation exists for the selection of this rare arrangement. In an effort to characterize the function of the tandem ACP arrangement, we have expressed individual and tandem ACP in E coli. Structure of tandem ACP in solution was determined by small angle X‐ray scattering (SAXS) in combination with circular dichroism (CD) and differential scanning calorimetry (DSC). SAXS shows that tandem ACP exhibits a flexible beads‐on‐string arrangement. The structural model of tandem ACP was validated by CD and DSC, which show that ACPs are stable and mainly composed of alpha‐helices. Interactions between DH and ACP domains with different bound acyl intermediates, were measured by microscale thermophoresis (MST). A binding affinity [Kd = 306 nM] varies with the acyl intermediate. The results from this work help us to gain insight into the role of tandem ACP arrangement in the biosynthesis of omega‐3 fatty acids. This work was funded by MBRS‐RISE Program, Grant R25GM061838 and NSF Grant CHE0953254.