title: Overexpression, purification, and characterization of recombinant Ca-ATPase regulators for high-resolution solution and solid-state NMR studies.
abstract: Phospholamban (PLB) and Sarcolipin (SLN) are integral membrane proteins that regulate muscle contractility via direct interaction with the Ca-ATPase in cardiac and skeletal muscle, respectively. The molecular details of these protein-protein interactions are as yet undetermined. Solution and solid-state NMR spectroscopies have proven to be effective tools for deciphering such regulatory mechanisms to a high degree of resolution; however, large quantities of pure recombinant protein are required for these studies. Thus, recombinant PLB and SLN production in Escherichia coli was optimized for use in NMR experiments. Fusions of PLB and SLN to maltose binding protein (MBP) were constructed and optimal conditions for protein expression and purification were screened. This facilitated the large-scale production of highly pure protein. To confirm their functionality, the biological activities of recombinant PLB and SLN were compared to those of their synthetic counterparts. The regulation of Ca-ATPase activity by recombinant PLB and SLN was indistinguishable from the regulation by synthetic proteins, demonstrating the functional integrity of the recombinant constructs and ensuring the biological relevance of our future structural studies. Finally, NMR spectroscopic conditions were established and optimized for use in investigations of the mechanism of Ca-ATPase regulation by PLB and SLN.
authors.affiliation: Department of Chemistry, University of Minnesota, 207 Pleasant St. S.E. Minneapolis, MN 55455, USA.
authors.forename: Bethany
authors.initials: B
authors.lastname: Buck
authors.forename: Jamillah
authors.initials: J
authors.lastname: Zamoon
authors.forename: Tara L
authors.initials: TL
authors.lastname: Kirby
authors.forename: Tara M
authors.initials: TM
authors.lastname: DeSilva
authors.forename: Christine
authors.initials: C
authors.lastname: Karim
authors.forename: David
authors.initials: D
authors.lastname: Thomas
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Veglia
mesh_terms: D000595:Amino Acid Sequence; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D011510:Proteolipids / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification; D012996:Solutions; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000099211:Phospholamban
chemical_list: D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D009124:Muscle Proteins; D011510:Proteolipids; D011993:Recombinant Fusion Proteins; D012996:Solutions; D000099211:Phospholamban; C077258:sarcolipin