1
|
Cleary SR, Seflova J, Cho EE, Bisht K, Khandelia H, Espinoza-Fonseca LM, Robia SL. Phospholamban inhibits the cardiac calcium pump by interrupting an allosteric activation pathway. J Biol Chem 2024; 300:107267. [PMID: 38583863 PMCID: PMC11098958 DOI: 10.1016/j.jbc.2024.107267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 03/20/2024] [Accepted: 04/02/2024] [Indexed: 04/09/2024] Open
Abstract
Phospholamban (PLB) is a transmembrane micropeptide that regulates the sarcoplasmic reticulum Ca2+-ATPase (SERCA) in cardiac muscle, but the physical mechanism of this regulation remains poorly understood. PLB reduces the Ca2+ sensitivity of active SERCA, increasing the Ca2+ concentration required for pump cycling. However, PLB does not decrease Ca2+ binding to SERCA when ATP is absent, suggesting PLB does not inhibit SERCA Ca2+ affinity. The prevailing explanation for these seemingly conflicting results is that PLB slows transitions in the SERCA enzymatic cycle associated with Ca2+ binding, altering transport Ca2+ dependence without actually affecting the equilibrium binding affinity of the Ca2+-coordinating sites. Here, we consider another hypothesis, that measurements of Ca2+ binding in the absence of ATP overlook important allosteric effects of nucleotide binding that increase SERCA Ca2+ binding affinity. We speculated that PLB inhibits SERCA by reversing this allostery. To test this, we used a fluorescent SERCA biosensor to quantify the Ca2+ affinity of non-cycling SERCA in the presence and absence of a non-hydrolyzable ATP-analog, AMPPCP. Nucleotide activation increased SERCA Ca2+ affinity, and this effect was reversed by co-expression of PLB. Interestingly, PLB had no effect on Ca2+ affinity in the absence of nucleotide. These results reconcile the previous conflicting observations from ATPase assays versus Ca2+ binding assays. Moreover, structural analysis of SERCA revealed a novel allosteric pathway connecting the ATP- and Ca2+-binding sites. We propose this pathway is disrupted by PLB binding. Thus, PLB reduces the equilibrium Ca2+ affinity of SERCA by interrupting allosteric activation of the pump by ATP.
Collapse
Affiliation(s)
- Sean R Cleary
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Ellen E Cho
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA
| | - Konark Bisht
- Department of Physics, Chemistry, and Pharmacy, PHYLIFE: Physical Life Science, University of Southern Denmark, Odense, Denmark
| | - Himanshu Khandelia
- Department of Physics, Chemistry, and Pharmacy, PHYLIFE: Physical Life Science, University of Southern Denmark, Odense, Denmark
| | - L Michel Espinoza-Fonseca
- Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois, USA.
| |
Collapse
|
2
|
Young MR, Heit S, Bublitz M. Structure, function and biogenesis of the fungal proton pump Pma1. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119600. [PMID: 37741574 DOI: 10.1016/j.bbamcr.2023.119600] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/19/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023]
Abstract
The fungal plasma membrane proton pump Pma1 is an integral plasma membrane protein of the P-type ATPase family. It is an essential enzyme responsible for maintaining a constant cytosolic pH and for energising the plasma membrane to secondary transport processes. Due to its importance for fungal survival and absence from animals, Pma1 is also a highly sought-after drug target. Until recently, its characterisation has been limited to functional, mutational and localisation studies, due to a lack of high-resolution structural information. The determination of three cryo-EM structures of Pma1 in its unique hexameric state offers a new level of understanding the molecular mechanisms underlying the protein's stability, regulated activity and druggability. In light of this context, this article aims to review what we currently know about the structure, function and biogenesis of fungal Pma1.
Collapse
Affiliation(s)
- Margaret R Young
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Sabine Heit
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
| |
Collapse
|
3
|
Kanai R, Vilsen B, Cornelius F, Toyoshima C. Crystal structures of Na + ,K + -ATPase reveal the mechanism that converts the K + -bound form to Na + -bound form and opens and closes the cytoplasmic gate. FEBS Lett 2023; 597:1957-1976. [PMID: 37357620 DOI: 10.1002/1873-3468.14689] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 06/27/2023]
Abstract
Na+ ,K+ -ATPase (NKA) plays a pivotal role in establishing electrochemical gradients for Na+ and K+ across the cell membrane by alternating between the E1 (showing high affinity for Na+ and low affinity for K+ ) and E2 (low affinity to Na+ and high affinity to K+ ) forms. Presented here are two crystal structures of NKA in E1·Mg2+ and E1·3Na+ states at 2.9 and 2.8 Å resolution, respectively. These two E1 structures fill a gap in our description of the NKA reaction cycle based on the atomic structures. We describe how NKA converts the K+ -bound E2·2K+ form to an E1 (E1·Mg2+ ) form, which allows high-affinity Na+ binding, eventually closing the cytoplasmic gate (in E1 ~ P·ADP·3Na+ ) after binding three Na+ , while keeping the extracellular ion pathway sealed. We now understand previously unknown functional roles for several parts of NKA and that NKA uses even the lipid bilayer for gating the ion pathway.
Collapse
Affiliation(s)
- Ryuta Kanai
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Bente Vilsen
- Department of Biomedicine, Aarhus University, Denmark
| | | | - Chikashi Toyoshima
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Japan
| |
Collapse
|
4
|
Pierantozzi E, Raucci L, Buonocore S, Rubino EM, Ding Q, Laurino A, Fiore F, Soldaini M, Chen J, Rossi D, Vangheluwe P, Chen H, Sorrentino V. Skeletal muscle overexpression of sAnk1.5 in transgenic mice does not predispose to type 2 diabetes. Sci Rep 2023; 13:8195. [PMID: 37210436 PMCID: PMC10199891 DOI: 10.1038/s41598-023-35393-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023] Open
Abstract
Genome-wide association studies (GWAS) and cis-expression quantitative trait locus (cis-eQTL) analyses indicated an association of the rs508419 single nucleotide polymorphism (SNP) with type 2 diabetes (T2D). rs508419 is localized in the muscle-specific internal promoter (P2) of the ANK1 gene, which drives the expression of the sAnk1.5 isoform. Functional studies showed that the rs508419 C/C variant results in increased transcriptional activity of the P2 promoter, leading to higher levels of sAnk1.5 mRNA and protein in skeletal muscle biopsies of individuals carrying the C/C genotype. To investigate whether sAnk1.5 overexpression in skeletal muscle might predispose to T2D development, we generated transgenic mice (TgsAnk1.5/+) in which the sAnk1.5 coding sequence was selectively overexpressed in skeletal muscle tissue. TgsAnk1.5/+ mice expressed up to 50% as much sAnk1.5 protein as wild-type (WT) muscles, mirroring the difference reported between individuals with the C/C or T/T genotype at rs508419. However, fasting glucose levels, glucose tolerance, insulin levels and insulin response in TgsAnk1.5/+ mice did not differ from those of age-matched WT mice monitored over a 12-month period. Even when fed a high-fat diet, TgsAnk1.5/+ mice only presented increased caloric intake, but glucose disposal, insulin tolerance and weight gain were comparable to those of WT mice fed a similar diet. Altogether, these data indicate that sAnk1.5 overexpression in skeletal muscle does not predispose mice to T2D susceptibility.
Collapse
Affiliation(s)
- E Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - L Raucci
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - S Buonocore
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - E M Rubino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - Q Ding
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
| | - A Laurino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - F Fiore
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - M Soldaini
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - J Chen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), 3000, Leuven, Belgium
| | - D Rossi
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy
| | - P Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), 3000, Leuven, Belgium
| | - H Chen
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - V Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy.
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy.
| |
Collapse
|
5
|
Multiple sub-state structures of SERCA2b reveal conformational overlap at transition steps during the catalytic cycle. Cell Rep 2022; 41:111760. [PMID: 36476867 DOI: 10.1016/j.celrep.2022.111760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 09/06/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) pumps Ca2+ into the endoplasmic reticulum (ER). Herein, we present cryo-electron microscopy (EM) structures of three intermediates of SERCA2b: Ca2+-bound phosphorylated (E1P·2Ca2+) and Ca2+-unbound dephosphorylated (E2·Pi) intermediates and another between the E2P and E2·Pi states. Our cryo-EM analysis demonstrates that the E1P·2Ca2+ state exists in low abundance and preferentially transitions to an E2P-like structure by releasing Ca2+ and that the Ca2+ release gate subsequently undergoes stepwise closure during the dephosphorylation processes. Importantly, each intermediate adopts multiple sub-state structures including those like the next one in the catalytic series, indicating conformational overlap at transition steps, as further substantiated by atomistic molecular dynamic simulations of SERCA2b in a lipid bilayer. The present findings provide insight into how enzymes accelerate catalytic cycles.
Collapse
|
6
|
Guo Y, Zhang Y, Yan R, Huang B, Ye F, Wu L, Chi X, Shi Y, Zhou Q. Cryo-EM structures of recombinant human sodium-potassium pump determined in three different states. Nat Commun 2022; 13:3957. [PMID: 35803952 PMCID: PMC9270386 DOI: 10.1038/s41467-022-31602-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/24/2022] [Indexed: 11/09/2022] Open
Abstract
Sodium-Potassium Pump (Na+/K+-ATPase, NKA) is an ion pump that generates an electrochemical gradient of sodium and potassium ions across the plasma membrane by hydrolyzing ATP. During each Post-Albers cycle, NKA exchanges three cytoplasmic sodium ions for two extracellular potassium ions through alternating changes between the E1 and E2 states. Hitherto, several steps remained unknown during the complete working cycle of NKA. Here, we report cryo-electron microscopy (cryo-EM) structures of recombinant human NKA (hNKA) in three distinct states at 2.7–3.2 Å resolution, representing the E1·3Na and E1·3Na·ATP states with cytosolic gates open and the basic E2·[2K] state, respectively. This work provides the insights into the cytoplasmic Na+ entrance pathway and the mechanism of cytoplasmic gate closure coupled with ATP hydrolysis, filling crucial gaps in the structural elucidation of the Post-Albers cycle of NKA. Sodium-Potassium Pump (Na+/K+-ATPase, NKA) generates an electrochemical gradient of sodium and potassium ions across the plasma membrane by hydrolyzing ATP. Here, the authors report structures of human NKA providing insight into the cytoplasmic Na+ entrance and the cytoplasmic gate closure coupled to ATP hydrolysis.
Collapse
Affiliation(s)
- Yingying Guo
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yuanyuan Zhang
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Renhong Yan
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Department of Biochemistry, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Bangdong Huang
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Fangfei Ye
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Liushu Wu
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Ximin Chi
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Yi Shi
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China
| | - Qiang Zhou
- Westlake Laboratory of Life Sciences and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China. .,Institute of Biology, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, China.
| |
Collapse
|
7
|
Zhang Y, Watanabe S, Tsutsumi A, Kadokura H, Kikkawa M, Inaba K. Cryo-EM analysis provides new mechanistic insight into ATP binding to Ca 2+ -ATPase SERCA2b. EMBO J 2021; 40:e108482. [PMID: 34459010 DOI: 10.15252/embj.2021108482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/31/2022] Open
Abstract
Sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA) 2b is a ubiquitous SERCA family member that conducts Ca2+ uptake from the cytosol to the ER. Herein, we present a 3.3 Å resolution cryo-electron microscopy (cryo-EM) structure of human SERCA2b in the E1·2Ca2+ state, revealing a new conformation for Ca2+ -bound SERCA2b with a much closer arrangement of cytosolic domains than in the previously reported crystal structure of Ca2+ -bound SERCA1a. Multiple conformations generated by 3D classification of cryo-EM maps reflect the intrinsically dynamic nature of the cytosolic domains in this state. Notably, ATP binding residues of SERCA2b in the E1·2Ca2+ state are located at similar positions to those in the E1·2Ca2+ -ATP state; hence, the cryo-EM structure likely represents a preformed state immediately prior to ATP binding. Consistently, a SERCA2b mutant with an interdomain disulfide bridge that locks the closed cytosolic domain arrangement displayed significant autophosphorylation activity in the presence of Ca2+ . We propose a novel mechanism of ATP binding to SERCA2b.
Collapse
Affiliation(s)
- Yuxia Zhang
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Satoshi Watanabe
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Akihisa Tsutsumi
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Kadokura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| | - Masahide Kikkawa
- Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kenji Inaba
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan
| |
Collapse
|
8
|
Espinoza-Fonseca LM. Structural Basis for the Function of the C-Terminal Proton Release Pathway in the Calcium Pump. Int J Mol Sci 2021; 22:ijms22073507. [PMID: 33805255 PMCID: PMC8037123 DOI: 10.3390/ijms22073507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/22/2021] [Accepted: 03/25/2021] [Indexed: 11/16/2022] Open
Abstract
The calcium pump (sarco/endoplasmic reticulum Ca2+-ATPase, SERCA) plays a major role in calcium homeostasis in muscle cells by clearing cytosolic Ca2+ during muscle relaxation. Active Ca2+ transport by SERCA involves the structural transition from a low-Ca2+ affinity E2 state toward a high-Ca2+ affinity E1 state of the pump. This structural transition is accompanied by the countertransport of protons to stabilize the negative charge and maintain the structural integrity of the transport sites and partially compensate for the positive charges of the two Ca2+ ions passing through the membrane. X-ray crystallography studies have suggested that a hydrated pore located at the C-terminal domain of SERCA serves as a conduit for proton countertransport, but the existence and function of this pathway have not yet been fully characterized. We used atomistic simulations to demonstrate that in the protonated E2 state and the absence of initially bound water molecules, the C-terminal pore becomes hydrated in the nanosecond timescale. Hydration of the C-terminal pore is accompanied by the formation of water wires that connect the transport sites with the cytosol. Water wires are known as ubiquitous proton-transport devices in biological systems, thus supporting the notion that the C-terminal domain serves as a conduit for proton release. Additional simulations showed that the release of a single proton from the transport sites induces bending of transmembrane helix M5 and the interaction between residues Arg762 and Ser915. These structural changes create a physical barrier against full hydration of the pore and prevent the formation of hydrogen-bonded water wires once proton transport has occurred through this pore. Together, these findings support the notion that the C-terminal proton release pathway is a functional element of SERCA and also provide a mechanistic model for its operation in the catalytic cycle of the pump.
Collapse
Affiliation(s)
- L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
9
|
Barbot T, Beswick V, Montigny C, Quiniou É, Jamin N, Mouawad L. Deciphering the Mechanism of Inhibition of SERCA1a by Sarcolipin Using Molecular Simulations. Front Mol Biosci 2021; 7:606254. [PMID: 33614704 PMCID: PMC7890198 DOI: 10.3389/fmolb.2020.606254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/06/2020] [Indexed: 12/02/2022] Open
Abstract
SERCA1a is an ATPase calcium pump that transports Ca2+ from the cytoplasm to the sarco/endoplasmic reticulum lumen. Sarcolipin (SLN), a transmembrane peptide, regulates the activity of SERCA1a by decreasing its Ca2+ transport rate, but its mechanism of action is still not well-understood. To decipher this mechanism, we have performed normal mode analysis in the all-atom model, with the SERCA1a-SLN complex, or the isolated SERCA1a, embedded in an explicit membrane. The comparison of the results allowed us to provide an explanation at the atomic level for the action of SLN that is in good agreement with experimental observations. In our analyses, the presence of SLN locally perturbs the TM6 transmembrane helix and as a consequence modifies the position of D800, one of the key metal-chelating residues. Additionally, it reduces the flexibility of the gating residues, V304, and E309 in TM4, at the entrance of the Ca2+ binding sites, which would decrease the affinity for Ca2+. Unexpectedly, SLN has also an effect on the ATP binding site more than 35 Å away, due to the straightening of TM5, a long helix considered as the spine of the protein. The straightening of TM5 modifies the structure of the P-N linker that sits above it, and which comprises the 351DKTG354 conserved motif, resulting in an increase of the distance between ATP and the phosphorylation site. As a consequence, the turn-over rate could be affected. All this gives SERCA1a the propensity to go toward a Ca2+ low-affinity E2-like state in the presence of SLN and toward a Ca2+ high-affinity E1-like state in the absence of SLN. In addition to a general mechanism of inhibition of SERCA1a regulatory peptides, this study also provides an insight into the conformational transition between the E2 and E1 states.
Collapse
Affiliation(s)
- Thomas Barbot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Veronica Beswick
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France.,Physics Department, Evry-Val-d'Essonne University, Paris-Saclay University, Evry, France
| | - Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Éric Quiniou
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
| | - Nadège Jamin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Liliane Mouawad
- CNRS UMR9187 / INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, Orsay, France
| |
Collapse
|
10
|
Dyla M, Kjærgaard M, Poulsen H, Nissen P. Structure and Mechanism of P-Type ATPase Ion Pumps. Annu Rev Biochem 2020; 89:583-603. [PMID: 31874046 DOI: 10.1146/annurev-biochem-010611-112801] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
P-type ATPases are found in all kingdoms of life and constitute a wide range of cation transporters, primarily for H+, Na+, K+, Ca2+, and transition metal ions such as Cu(I), Zn(II), and Cd(II). They have been studied through a wide range of techniques, and research has gained very significant insight on their transport mechanism and regulation. Here, we review the structure, function, and dynamics of P2-ATPases including Ca2+-ATPases and Na,K-ATPase. We highlight mechanisms of functional transitions that are associated with ion exchange on either side of the membrane and how the functional cycle is regulated by interaction partners, autoregulatory domains, and off-cycle states. Finally, we discuss future perspectives based on emerging techniques and insights.
Collapse
Affiliation(s)
- Mateusz Dyla
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; .,Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic European Molecular Biology Laboratory (EMBL) Partnership for Molecular Medicine, 8000 Aarhus, Denmark
| | - Magnus Kjærgaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; .,Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic European Molecular Biology Laboratory (EMBL) Partnership for Molecular Medicine, 8000 Aarhus, Denmark
| | - Hanne Poulsen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; .,Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic European Molecular Biology Laboratory (EMBL) Partnership for Molecular Medicine, 8000 Aarhus, Denmark
| | - Poul Nissen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark; .,Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic European Molecular Biology Laboratory (EMBL) Partnership for Molecular Medicine, 8000 Aarhus, Denmark
| |
Collapse
|
11
|
The SERCA residue Glu340 mediates interdomain communication that guides Ca 2+ transport. Proc Natl Acad Sci U S A 2020; 117:31114-31122. [PMID: 33229570 PMCID: PMC7733806 DOI: 10.1073/pnas.2014896117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
We present a crystal structure, functional data, and molecular dynamics (MD) simulations of the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) mutant E340A. The mutation slows Ca2+-binding kinetics, and the structural differences between wild type and E340A indicate that the mutation disrupts a central interdomain “communication hub” governing Ca2+ binding/dissociation. MD simulations reveal altered dynamics in regions mediating Ca2+ occlusion, a critical step in SERCA’s alternating access mechanism. The mutation stabilizes a more occluded state of the Ca2+ sites. The strict conservation of Glu340 among P-type ATPases is the result of its critical role in interdomain communication between the cytosolic headpiece and the transmembrane domain, ensuring a delicate balance between dynamics of ion binding, occlusion, and release—key steps in the transport process. The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a P-type ATPase that transports Ca2+ from the cytosol into the sarco(endo)plasmic reticulum (SR/ER) lumen, driven by ATP. This primary transport activity depends on tight coupling between movements of the transmembrane helices forming the two Ca2+-binding sites and the cytosolic headpiece mediating ATP hydrolysis. We have addressed the molecular basis for this intramolecular communication by analyzing the structure and functional properties of the SERCA mutant E340A. The mutated Glu340 residue is strictly conserved among the P-type ATPase family of membrane transporters and is located at a seemingly strategic position at the interface between the phosphorylation domain and the cytosolic ends of 5 of SERCA’s 10 transmembrane helices. The mutant displays a marked slowing of the Ca2+-binding kinetics, and its crystal structure in the presence of Ca2+ and ATP analog reveals a rotated headpiece, altered connectivity between the cytosolic domains, and an altered hydrogen bonding pattern around residue 340. Supported by molecular dynamics simulations, we conclude that the E340A mutation causes a stabilization of the Ca2+ sites in a more occluded state, hence displaying slowed dynamics. This finding underpins a crucial role of Glu340 in interdomain communication between the headpiece and the Ca2+-binding transmembrane region.
Collapse
|
12
|
Aguayo-Ortiz R, Espinoza-Fonseca LM. Atomistic Structure and Dynamics of the Ca 2+-ATPase Bound to Phosphorylated Phospholamban. Int J Mol Sci 2020; 21:ijms21197261. [PMID: 33019581 PMCID: PMC7583845 DOI: 10.3390/ijms21197261] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 09/29/2020] [Accepted: 09/29/2020] [Indexed: 01/22/2023] Open
Abstract
Sarcoplasmic reticulum Ca2+-ATPase (SERCA) and phospholamban (PLB) are essential components of the cardiac Ca2+ transport machinery. PLB phosphorylation at residue Ser16 (pSer16) enhances SERCA activity in the heart via an unknown structural mechanism. Here, we report a fully atomistic model of SERCA bound to phosphorylated PLB and study its structural dynamics on the microsecond time scale using all-atom molecular dynamics simulations in an explicit lipid bilayer and water environment. The unstructured N-terminal phosphorylation domain of PLB samples different orientations and covers a broad area of the cytosolic domain of SERCA but forms a stable complex mediated by pSer16 interactions with a binding site formed by SERCA residues Arg324/Lys328. PLB phosphorylation does not affect the interaction between the transmembrane regions of the two proteins; however, pSer16 stabilizes a disordered structure of the N-terminal phosphorylation domain that releases key inhibitory contacts between SERCA and PLB. We found that PLB phosphorylation is sufficient to guide the structural transitions of the cytosolic headpiece that are required to produce a competent structure of SERCA. We conclude that PLB phosphorylation serves as an allosteric molecular switch that releases inhibitory contacts and strings together the catalytic elements required for SERCA activation. This atomistic model represents a vivid atomic-resolution visualization of SERCA bound to phosphorylated PLB and provides previously inaccessible insights into the structural mechanism by which PLB phosphorylation releases SERCA inhibition in the heart.
Collapse
Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA;
- Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - L. Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA;
- Correspondence: ; Tel.: +1-734-998-7500
| |
Collapse
|
13
|
Dimerization of SERCA2a Enhances Transport Rate and Improves Energetic Efficiency in Living Cells. Biophys J 2020; 119:1456-1465. [PMID: 32946770 DOI: 10.1016/j.bpj.2020.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/07/2020] [Accepted: 08/25/2020] [Indexed: 11/21/2022] Open
Abstract
The type 2a sarco/endoplasmic reticulum (ER) Ca2+-ATPase (SERCA2a) plays a key role in intracellular Ca2+ regulation in the heart. We have previously shown evidence of stable homodimers of SERCA2a in heterologous cells and cardiomyocytes. However, the functional significance of the pump dimerization remains unclear. Here, we analyzed how SERCA2a dimerization affects ER Ca2+ transport. Fluorescence resonance energy transfer experiments in HEK293 cells transfected with fluorescently labeled SERCA2a revealed increasing dimerization of Ca2+ pumps with increasing expression level. This concentration-dependent dimerization provided means of comparison of the functional characteristics of monomeric and dimeric pumps. SERCA-mediated Ca2+ uptake was measured with the ER-targeted Ca2+ sensor R-CEPIA1er in cells cotransfected with SERCA2a and ryanodine receptor. For each individual cell, the maximal ER Ca2+ uptake rate and the maximal Ca2+ load, together with the pump expression level, were analyzed. This analysis revealed that the ER Ca2+ uptake rate increased as a function of SERCA2a expression, with a particularly steep, nonlinear increase at high expression levels. Interestingly, the maximal ER Ca2+ load also increased with an increase in the pump expression level, suggesting improved catalytic efficiency of the dimeric species. Reciprocally, thapsigargin inhibition of a fraction of the population of SERCA2a reduced not only the maximal ER Ca2+ uptake rate but also the maximal Ca2+ load. These data suggest that SERCA2a dimerization regulates Ca2+ transport by improving both the SERCA2a turnover rate and catalytic efficacy. Analysis of ER Ca2+ uptake in cells cotransfected with human wild-type SERCA2a (SERCA2aWT) and SERCA2a mutants with different catalytic activity revealed that an intact catalytic cycle in both protomers is required for enhancing the efficacy of Ca2+ transport by a dimer. The data are consistent with the hypothesis of functional coupling of two SERCA2a protomers in a dimer that reduces the energy barrier of rate-limiting steps of the catalytic cycle of Ca2+ transport.
Collapse
|
14
|
Aguayo-Ortiz R, Espinoza-Fonseca LM. Linking Biochemical and Structural States of SERCA: Achievements, Challenges, and New Opportunities. Int J Mol Sci 2020; 21:ijms21114146. [PMID: 32532023 PMCID: PMC7313052 DOI: 10.3390/ijms21114146] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 02/07/2023] Open
Abstract
Sarcoendoplasmic reticulum calcium ATPase (SERCA), a member of the P-type ATPase family of ion and lipid pumps, is responsible for the active transport of Ca2+ from the cytoplasm into the sarcoplasmic reticulum lumen of muscle cells, into the endoplasmic reticulum (ER) of non-muscle cells. X-ray crystallography has proven to be an invaluable tool in understanding the structural changes of SERCA, and more than 70 SERCA crystal structures representing major biochemical states (defined by bound ligand) have been deposited in the Protein Data Bank. Consequently, SERCA is one of the best characterized components of the calcium transport machinery in the cell. Emerging approaches in the field, including spectroscopy and molecular simulation, now help integrate and interpret this rich structural information to understand the conformational transitions of SERCA that occur during activation, inhibition, and regulation. In this review, we provide an overview of the crystal structures of SERCA, focusing on identifying metrics that facilitate structure-based categorization of major steps along the catalytic cycle. We examine the integration of crystallographic data with different biophysical approaches and computational methods to link biochemical and structural states of SERCA that are populated in the cell. Finally, we discuss the challenges and new opportunities in the field, including structural elucidation of functionally important and novel regulatory complexes of SERCA, understanding the structural basis of functional divergence among homologous SERCA regulators, and bridging the gap between basic and translational research directed toward therapeutic modulation of SERCA.
Collapse
|
15
|
Fernández-de Gortari E, Aguayo-Ortiz R, Autry JM, Michel Espinoza-Fonseca L. A hallmark of phospholamban functional divergence is located in the N-terminal phosphorylation domain. Comput Struct Biotechnol J 2020; 18:705-713. [PMID: 32257054 PMCID: PMC7114604 DOI: 10.1016/j.csbj.2020.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/23/2020] [Accepted: 02/23/2020] [Indexed: 01/12/2023] Open
Abstract
Sarcoplasmic reticulum Ca2+ pump (SERCA) is a critical component of the Ca2+ transport machinery in myocytes. There is clear evidence for regulation of SERCA activity by PLB, whose activity is modulated by phosphorylation of its N-terminal domain (residues 1–25), but there is less clear evidence for the role of this domain in PLB’s functional divergence. It is widely accepted that only sarcolipin (SLN), a protein that shares substantial homology with PLB, uncouples SERCA Ca2+ transport from ATP hydrolysis by inducing a structural change of its energy-transduction domain; yet, experimental evidence shows that the transmembrane domain of PLB (residues 26–52, PLB26–52) partially uncouples SERCA in vitro. These apparently conflicting mechanisms suggest that PLB’s uncoupling activity is encoded in its transmembrane domain, and that it is controlled by the N-terminal phosphorylation domain. To test this hypothesis, we performed molecular dynamics simulations (MDS) of the binary complex between PLB26–52 and SERCA. Comparison between PLB26–52 and wild-type PLB (PLBWT) showed no significant changes in the stability and orientation of the transmembrane helix, indicating that PLB26–52 forms a native-like complex with SERCA. MDS showed that PLB26–52 produces key intermolecular contacts and structural changes required for inhibition, in agreement with studies showing that PLB26–52 inhibits SERCA. However, deletion of the N-terminal phosphorylation domain facilitates an order-to-disorder shift in the energy-transduction domain associated with uncoupling of SERCA, albeit weaker than that induced by SLN. This mechanistic evidence reveals that the N-terminal phosphorylation domain of PLB is a primary contributor to the functional divergence among homologous SERCA regulators.
Collapse
Affiliation(s)
- Eli Fernández-de Gortari
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Rodrigo Aguayo-Ortiz
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joseph M Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.,Biophysical Technology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
16
|
Structural dynamics of P-type ATPase ion pumps. Biochem Soc Trans 2020; 47:1247-1257. [PMID: 31671180 DOI: 10.1042/bst20190124] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/06/2019] [Accepted: 09/16/2019] [Indexed: 02/04/2023]
Abstract
P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.
Collapse
|
17
|
General and specific interactions of the phospholipid bilayer with P-type ATPases. Biophys Rev 2019; 11:353-364. [PMID: 31073955 DOI: 10.1007/s12551-019-00533-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 04/25/2019] [Indexed: 12/14/2022] Open
Abstract
Protein structure and function are modulated via interactions with their environment, representing both the surrounding aqueous media and lipid membranes that have an active role in shaping the structural topology of membrane proteins. Compared to a decade ago, there is now an abundance of crystal structural data on membrane proteins, which together with their functional studies have enhanced our understanding of the salient features of lipid-protein interactions. It is now important to recognize that membrane proteins are regulated by both (1) general lipid-protein interactions, where the general physicochemical properties of the lipid environment affect the conformational flexibility of a membrane protein, and (2) by specific lipid-protein interactions, where lipid molecules directly interact via chemical interactions with specific lipid-binding sites located on the protein. However, due to local differences in membrane composition, thickness, and lipid packing, local membrane physical properties and hence the associated lipid-protein interactions also differ due to membrane location, even for the same protein. Such a phenomenon has been shown to be true for one family of integral membrane ion pumps, the P2-type adenosine triphosphatases (ATPases). Despite being highly homologous, individual members of this family have distinct structural and functional activity and are an excellent candidate to highlight how the local membrane physical properties and specific lipid-protein interactions play a vital role in facilitating the structural rearrangements of these proteins necessary for their activity. Hence in this review, we focus on both the general and specific lipid-protein interactions and will mostly discuss the structure-function relationships of the following P2-type ATPases, Na+,K+-ATPase (NKA), gastric H+,K+-ATPase (HKA), and sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), in concurrence with their lipid environment.
Collapse
|
18
|
Sun B, Stewart BD, Kucharski AN, Kekenes-Huskey PM. Thermodynamics of Cation Binding to the Sarcoendoplasmic Reticulum Calcium ATPase Pump and Impacts on Enzyme Function. J Chem Theory Comput 2019; 15:2692-2705. [PMID: 30807147 DOI: 10.1021/acs.jctc.8b01312] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) is a transmembrane pump that plays an important role in transporting calcium into the sarcoplasmic reticulum (SR). While calcium (Ca2+) binds SERCA with micromolar affinity, magnesium (Mg2+) and potassium (K+) also compete with Ca2+ binding. However, the molecular bases for these competing ions' influence on the SERCA function and the selectivity of the pump for Ca2+ are not well-established. We therefore used in silico methods to resolve molecular determinants of cation binding in the canonical site I and II Ca2+ binding sites via (1) triplicate molecular dynamics (MD) simulations of Mg2+, Ca2+, and K+-bound SERCA, (2) mean spherical approximation (MSA) theory to score the affinity and selectivity of cation binding to the MD-resolved structures, and (3) state models of SERCA turnover informed from MSA-derived affinity data. Our key findings are that (a) coordination at sites I and II is optimized for Ca2+ and to a lesser extent for Mg2+ and K+, as determined by MD-derived cation-amino acid oxygen and bound water configurations, (b) the impaired coordination and high desolvation cost for Mg2+ precludes favorable Mg2+ binding relative to Ca2+, while K+ has limited capacity to bind site I, and (c) Mg2+ most likely acts as inhibitor and K+ as intermediate in SERCA's reaction cycle, based on a best-fit state model of SERCA turnover. These findings provide a quantitative basis for SERCA function that leverages molecular-scale thermodynamic data and rationalizes enzyme activity across broad ranges of K+, Ca2+, and Mg2+ concentrations.
Collapse
Affiliation(s)
- Bin Sun
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Bradley D Stewart
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Amir N Kucharski
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Peter M Kekenes-Huskey
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States.,Department of Chemical and Materials Engineering , University of Kentucky , 177 F. Paul Anderson Tower , Lexington , Kentucky 40506 , United States
| |
Collapse
|
19
|
Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
![]()
Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
Collapse
Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
| |
Collapse
|
20
|
Lenoir G, Dieudonné T, Lamy A, Lejeune M, Vazquez-Ibar JL, Montigny C. Screening of Detergents for Stabilization of Functional Membrane Proteins. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2018; 93:e59. [PMID: 30021058 DOI: 10.1002/cpps.59] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Membrane protein studies usually require use of detergents to extract and isolate proteins from membranes and manipulate them in a soluble context for their functional or structural characterization. However, solubilization with detergent may interfere with MP stability and may directly affect MP function or structure. Moreover, detergent properties can be affected such as critical micellar concentration (CMC) can be affected by the experimental conditions. Consequently, the experimenter must pay attention to both the protein and the behavior of the detergent. This article provides a convenient protocol for estimating the CMC of detergents in given experimental conditions. Then, it presents two protocols aimed at monitoring the function of a membrane protein in the presence of detergent. Such experiments may help to test various detergents for their inactivating or stabilizing effects on long incubation times, ranging from few hours to some days. © 2018 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Guillaume Lenoir
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Thibaud Dieudonné
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Anaïs Lamy
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Maylis Lejeune
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - José-Luis Vazquez-Ibar
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| | - Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette CEDEX, France
| |
Collapse
|
21
|
Yoo JI, O’Malley MA. Tuning Vector Stability and Integration Frequency Elevates Functional GPCR Production and Homogeneity in Saccharomyces cerevisiae. ACS Synth Biol 2018; 7:1763-1772. [PMID: 29871481 DOI: 10.1021/acssynbio.8b00036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane proteins play a valuable role in biotechnology, yet the difficulty of producing high yields of functional membrane protein limits their use in synthetic biology. The practical application of G protein-coupled receptors in whole cell biosensors, for example, is restricted to those that are functionally produced at the cell surface in the chosen host, limiting the range of detectable molecules. Here, we present a facile approach to significantly improve the yield and homogeneity of functional membrane proteins in Saccharomyces cerevisiae by altering only the choice of expression vector. Expression of a model GPCR, the human adenosine A2a receptor, from commonly used centromeric and episomal vectors leads to low yields and cellular heterogeneity due to plasmid loss in 20-90% of the cell population. In contrast, homogeneous production of GPCR is attained using a multisite integrating vector or a novel, modified high copy vector that does not require genomic integration or addition of any selection agents. Finally, we introduce a FACS-based screen, which enables rapid isolation of cells with 4- to 15-fold increases in gene dosage and up to a 9-fold increase in functional protein yield without loss of homogeneity compared to a strain isolated through conventional, low-throughput methods. These results can be extended to improve the cellular homogeneity and yield of other membrane proteins, expanding the repertoire of useful receptors for synthetic biology applications.
Collapse
Affiliation(s)
- Justin I. Yoo
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Michelle A. O’Malley
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| |
Collapse
|
22
|
Brunetti E, Moerkerke S, Wouters J, Bartik K, Jabin I. A selective calix[6]arene-based fluorescent chemosensor for phosphatidylcholine type lipids. Org Biomol Chem 2018; 14:10201-10207. [PMID: 27731470 DOI: 10.1039/c6ob01880g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The development of chemosensors that can selectively detect phosphatidylcholines (PCs) in biological samples is of medical relevance considering the importance of these phospholipids in cell growth and survival. Their selective sensing over phosphatidylethanolamines (PEs) is however a challenging task. We report here on the chemosensing capacities of calix[6]tris-pyrenylurea 1, which is able to selectively interact with phosphatidylcholine-type lipids in organic media. Host 1 also binds them in a biphasic chloroform/water solution, opening the way to the design of selective chemosensors for these lipids in biological media. The results obtained by NMR, fluorescence spectroscopy and modelling studies show that the selectivity is the result of the high degree of complementarity between the lipids' zwitterionic phosphatidylcholine headgroup and the receptor's H-bonding donor site and hydrophobic pocket. The mode of recognition is reminiscent of natural systems, such as human phosphatidylcholine transfer proteins (PC-TPs), validating the biomimetic approach adopted in our work.
Collapse
Affiliation(s)
- Emilio Brunetti
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium. and Engineering of Molecular NanoSystems, Ecole polytechnique de Bruxelles, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP165/64, B-1050 Brussels, Belgium.
| | - Steven Moerkerke
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
| | - Johan Wouters
- Département de Chimie, Université de Namur (UNamur), Rue de Bruxelles 61, B5-5000 Namur, Belgium
| | - Kristin Bartik
- Engineering of Molecular NanoSystems, Ecole polytechnique de Bruxelles, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP165/64, B-1050 Brussels, Belgium.
| | - Ivan Jabin
- Laboratoire de Chimie Organique, Université libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium.
| |
Collapse
|
23
|
Yamasaki K, Daiho T, Danko S, Yasuda S, Suzuki H. Nanodisc-based kinetic assays reveal distinct effects of phospholipid headgroups on the phosphoenzyme transition of sarcoplasmic reticulum Ca 2+-ATPase. J Biol Chem 2017; 292:20218-20227. [PMID: 29032359 DOI: 10.1074/jbc.m117.816702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/10/2017] [Indexed: 01/08/2023] Open
Abstract
Sarco(endo)plasmic reticulum Ca2+-ATPase catalyzes ATP-driven Ca2+ transport from the cytoplasm to the lumen and is critical for a range of cell functions, including muscle relaxation. Here, we investigated the effects of the headgroups of the 1-palmitoyl-2-oleoyl glycerophospholipids phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylglycerol (PG) on sarcoplasmic reticulum (SR) Ca2+-ATPase embedded into a nanodisc, a lipid-bilayer construct harboring the specific lipid. We found that Ca2+-ATPase activity in a PC bilayer is comparable with that of SR vesicles and is suppressed in the other phospholipids, especially in PS. Ca2+ affinity at the high-affinity transport sites in PC was similar to that of SR vesicles, but 2-3-fold reduced in PE and PS. Ca2+ on- and off-rates in the non-phosphorylated ATPase were markedly reduced in PS. Rate-limiting phosphoenzyme (EP) conformational transition in 0.1 m KCl was as rapid in PC as in SR vesicles, but slowed in other phospholipids, especially in PS. Using kinetic plots of the logarithm of rate versus the square of mean activity coefficient of solutes in 0.1-1 m KCl, we noted that PC is optimal for the EP transition, but PG and especially PS had markedly unfavorable electrostatic effects, and PE exhibited a strong non-electrostatic restriction. Thus, the major SR membrane lipid PC is optimal for all steps and, unlike the other headgroups, contributes favorable electrostatics and non-electrostatic elements during the EP transition. Our analyses further revealed that the surface charge of the lipid bilayer directly modulates the transition rate.
Collapse
Affiliation(s)
- Kazuo Yamasaki
- Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan.
| | - Takashi Daiho
- Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Stefania Danko
- Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Satoshi Yasuda
- Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| | - Hiroshi Suzuki
- Department of Biochemistry, Asahikawa Medical University, Midorigaoka-Higashi, Asahikawa 078-8510, Japan
| |
Collapse
|
24
|
Tejral G, Sopko B, Necas A, Schoner W, Amler E. Computer modelling reveals new conformers of the ATP binding loop of Na +/K +-ATPase involved in the transphosphorylation process of the sodium pump. PeerJ 2017; 5:e3087. [PMID: 28316890 PMCID: PMC5354106 DOI: 10.7717/peerj.3087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/14/2017] [Indexed: 01/02/2023] Open
Abstract
Hydrolysis of ATP by Na+/K+-ATPase, a P-Type ATPase, catalyzing active Na+ and K+ transport through cellular membranes leads transiently to a phosphorylation of its catalytical α-subunit. Surprisingly, three-dimensional molecular structure analysis of P-type ATPases reveals that binding of ATP to the N-domain connected by a hinge to the P-domain is much too far away from the Asp369 to allow the transfer of ATP’s terminal phosphate to its aspartyl-phosphorylation site. In order to get information for how the transfer of the γ-phosphate group of ATP to the Asp369 is achieved, analogous molecular modeling of the M4–M5 loop of ATPase was performed using the crystal data of Na+/K+-ATPase of different species. Analogous molecular modeling of the cytoplasmic loop between Thr338 and Ile760 of the α2-subunit of Na+/K+-ATPase and the analysis of distances between the ATP binding site and phosphorylation site revealed the existence of two ATP binding sites in the open conformation; the first one close to Phe475 in the N-domain, the other one close to Asp369 in the P-domain. However, binding of Mg2+•ATP to any of these sites in the “open conformation” may not lead to phosphorylation of Asp369. Additional conformations of the cytoplasmic loop were found wobbling between “open conformation” <==> “semi-open conformation <==> “closed conformation” in the absence of 2Mg2+•ATP. The cytoplasmic loop’s conformational change to the “semi-open conformation”—characterized by a hydrogen bond between Arg543 and Asp611—triggers by binding of 2Mg2+•ATP to a single ATP site and conversion to the “closed conformation” the phosphorylation of Asp369 in the P-domain, and hence the start of Na+/K+-activated ATP hydrolysis.
Collapse
Affiliation(s)
- Gracian Tejral
- Department of Biophysics, 2nd Faculty of Medicine, Charles University Prague, Prague, Czech Republic; Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Bruno Sopko
- Department of Medical Chemistry and Clinical Biochemistry, 2nd Faculty of Medicine, Charles University Prague , Prague , Czech Republic
| | - Alois Necas
- Small Animal Clinic, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Science , Brno , Czech Republic
| | - Wilhelm Schoner
- Institute of Biochemistry and Endocrinology, University of Giessen , Giessen , Germany
| | - Evzen Amler
- Department of Biophysics, 2nd Faculty of Medicine, Charles University Prague, Prague, Czech Republic; Laboratory of Tissue Engineering, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| |
Collapse
|
25
|
Autry JM, Thomas DD, Espinoza-Fonseca LM. Sarcolipin Promotes Uncoupling of the SERCA Ca 2+ Pump by Inducing a Structural Rearrangement in the Energy-Transduction Domain. Biochemistry 2016; 55:6083-6086. [PMID: 27731980 PMCID: PMC5506494 DOI: 10.1021/acs.biochem.6b00728] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have performed microsecond (μs) molecular dynamics simulation (MDS) to identify structural mechanisms for sarcolipin (SLN) uncoupling of Ca2+ transport from ATP hydrolysis for the sarcoplasmic reticulum Ca2+-ATPase (SERCA). SLN regulates muscle metabolism and energy expenditure to provide resistance against diet-induced obesity and extreme cold. MDS demonstrated that the cytosolic domain of SLN induces a salt bridge-mediated structural rearrangement in the energy-transduction domain of SERCA. We propose that this structural change uncouples SERCA by perturbing Ca2+ occlusion at residue E309 in transport site II, thus facilitating Ca2+ backflux to the cytosol. Our results have important implications for designing muscle-based therapies for human obesity.
Collapse
Affiliation(s)
- Joseph M. Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
- Biophysical Technology Center, University of Minnesota, Minneapolis, MN 55455
| | - David D. Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| | - L. Michel Espinoza-Fonseca
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
| |
Collapse
|
26
|
Clausen JD, McIntosh DB, Woolley DG, Andersen JP. Determination of the ATP Affinity of the Sarcoplasmic Reticulum Ca(2+)-ATPase by Competitive Inhibition of [γ-(32)P]TNP-8N3-ATP Photolabeling. Methods Mol Biol 2016; 1377:233-59. [PMID: 26695037 DOI: 10.1007/978-1-4939-3179-8_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoactivation of aryl azides is commonly employed as a means to covalently attach cross-linking and labeling reagents to proteins, facilitated by the high reactivity of the resultant aryl nitrenes with amino groups present in the protein side chains. We have developed a simple and reliable assay for the determination of the ATP binding affinity of native or recombinant sarcoplasmic reticulum Ca(2+)-ATPase, taking advantage of the specific photolabeling of Lys(492) in the Ca(2+)-ATPase by [γ-(32)P]2',3'-O-(2,4,6-trinitrophenyl)-8-azido-adenosine 5'-triphosphate ([γ-(32)P]TNP-8N3-ATP) and the competitive inhibition by ATP of the photolabeling reaction. The method allows determination of the ATP affinity of Ca(2+)-ATPase mutants expressed in mammalian cell culture in amounts too minute for conventional equilibrium binding studies. Here, we describe the synthesis and purification of the [γ-(32)P]TNP-8N3-ATP photolabel, as well as its application in ATP affinity measurements.
Collapse
Affiliation(s)
- Johannes D Clausen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Building 1160, 8000, Aarhus C, Denmark.
| | - David B McIntosh
- Institute of Infectious Diseases and Molecular Medicine, Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - David G Woolley
- Institute of Infectious Diseases and Molecular Medicine, Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, South Africa
| | - Jens Peter Andersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Building 1160, 8000, Aarhus C, Denmark
| |
Collapse
|
27
|
Smaardijk S, Chen J, Wuytack F, Vangheluwe P. SPCA2 couples Ca 2+ influx via Orai1 to Ca 2+ uptake into the Golgi/secretory pathway. Tissue Cell 2016; 49:141-149. [PMID: 27692665 DOI: 10.1016/j.tice.2016.09.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/29/2016] [Accepted: 09/02/2016] [Indexed: 11/25/2022]
Abstract
Dysregulation of the Golgi/Secretory Pathway Ca2+ transport ATPase SPCA2 is implicated in breast cancer. During lactation and in luminal breast cancer types, SPCA2 interacts with the plasma membrane Ca2+ channel Orai1, promoting constitutive Ca2+ influx, which is termed store independent Ca2+ entry (SICE). The mechanism of SPCA2/Orai1 interaction depends on the N- and C-termini of SPCA2. These extensions may play a dual role in activating not only Orai1, but also Ca2+ transport into the Golgi/secretory pathway, which we tested by investigating the impact of various SPCA2 N- and/or C-terminal truncations on SICE and Ca2+ transport activity of SPCA2. C-terminal truncations impair SICE and SPCA2 activity, but also affect targeting, whereas N-terminal truncations affect targeting and inactivate SPCA2, but remarkably, SICE activation remains unaffected. Importantly, overexpression of SPCA2 increases the Ca2+ content of non-ER stores, which depends on Orai1 and SPCA2 activity. Thus, Orai1-mediated Ca2+-influx and SPCA2-mediated Ca2+ uptake activity into the Golgi/secretory pathway might be coupled possibly in a microdomain. This channel/pump complex may efficiently transfer Ca2+ into the secretory pathway, which might play a role in SPCA2-expressing secretory cells, such as mammary gland during lactation.
Collapse
Affiliation(s)
- Susanne Smaardijk
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jialin Chen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Frank Wuytack
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
| |
Collapse
|
28
|
Vostrikov VV, Gustavsson M, Gopinath T, Mullen D, Dicke AA, Truong V, Veglia G. Ca(2+) ATPase Conformational Transitions in Lipid Bilayers Mapped by Site-directed Ethylation and Solid-State NMR. ACS Chem Biol 2016; 11:329-34. [PMID: 26650884 DOI: 10.1021/acschembio.5b00953] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To transmit signals across cellular compartments, many membrane-embedded enzymes undergo extensive conformational rearrangements. Monitoring these events in lipid bilayers by NMR at atomic resolution has been challenging due to the large size of these systems. It is further exacerbated for large mammalian proteins that are difficult to express and label with NMR-active isotopes. Here, we synthesized and engineered (13)C ethyl groups on native cysteines to map the structural transitions of the sarcoplasmic reticulum Ca(2+)-ATPase, a 110 kDa transmembrane enzyme that transports Ca(2+) into the sarcoplasmic reticulum. Using magic angle spinning NMR, we monitored the chemical shifts of the methylene and methyl groups of the derivatized cysteine residues along the major steps of the enzymatic cycle. The methylene chemical shifts are sensitive to the ATPase conformational changes induced upon nucleotide and Ca(2+) ion binding and are ideal probes for active and inactive states of the enzyme. This new approach is extendable to large mammalian enzymes and signaling proteins with native or engineered cysteine residues in their amino acid sequence.
Collapse
Affiliation(s)
- Vitaly V. Vostrikov
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Martin Gustavsson
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Tata Gopinath
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Dan Mullen
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Alysha A. Dicke
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Vincent Truong
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Biophysics & Molecular Biology, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
29
|
Espinoza-Fonseca LM, Autry JM, Ramírez-Salinas GL, Thomas DD. Atomic-level mechanisms for phospholamban regulation of the calcium pump. Biophys J 2016; 108:1697-1708. [PMID: 25863061 DOI: 10.1016/j.bpj.2015.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 02/25/2015] [Accepted: 03/04/2015] [Indexed: 12/29/2022] Open
Abstract
We performed protein pKa calculations and molecular dynamics (MD) simulations of the calcium pump (sarcoplasmic reticulum Ca(2+)-ATPase (SERCA)) in complex with phospholamban (PLB). X-ray crystallography studies have suggested that PLB locks SERCA in a low-Ca(2+)-affinity E2 state that is incompatible with metal-ion binding, thereby blocking the conversion toward a high-Ca(2+)-affinity E1 state. Estimation of pKa values of the acidic residues in the transport sites indicates that at normal intracellular pH (7.1-7.2), PLB-bound SERCA populates an E1 state that is deprotonated at residues E309 and D800 yet protonated at residue E771. We performed three independent microsecond-long MD simulations to evaluate the structural dynamics of SERCA-PLB in a solution containing 100 mM K(+) and 3 mM Mg(2+). Principal component analysis showed that PLB-bound SERCA lies exclusively along the structural ensemble of the E1 state. We found that the transport sites of PLB-bound SERCA are completely exposed to the cytosol and that K(+) ions bind transiently (≤5 ns) and nonspecifically (nine different positions) to the two transport sites, with a total occupancy time of K(+) in the transport sites of 80%. We propose that PLB binding to SERCA populates a novel (to our knowledge) E1 intermediate, E1⋅H(+)771. This intermediate serves as a kinetic trap that controls headpiece dynamics and depresses the structural transitions necessary for Ca(2+)-dependent activation of SERCA. We conclude that PLB-mediated regulation of SERCA activity in the heart results from biochemical and structural transitions that occur primarily in the E1 state of the pump.
Collapse
Affiliation(s)
- L Michel Espinoza-Fonseca
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota.
| | - Joseph M Autry
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota
| | - G Lizbeth Ramírez-Salinas
- Laboratorio de Modelado Molecular y Bioinformática, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota
| |
Collapse
|
30
|
Azouaoui H, Montigny C, Jacquot A, Barry R, Champeil P, Lenoir G. Coordinated Overexpression in Yeast of a P4-ATPase and Its Associated Cdc50 Subunit: The Case of the Drs2p/Cdc50p Lipid Flippase Complex. Methods Mol Biol 2016; 1377:37-55. [PMID: 26695021 DOI: 10.1007/978-1-4939-3179-8_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Structural and functional characterization of integral membrane proteins requires milligram amounts of purified sample. Unless the protein you are studying is abundant in native membranes, it will be critical to overexpress the protein of interest in a homologous or heterologous way, and in sufficient quantities for further purification. The situation may become even more complicated if you chose to investigate the structure and function of a complex of two or more membrane proteins. Here, we describe the overexpression of a yeast lipid flippase complex, namely the P4-ATPase Drs2p and its associated subunit Cdc50p, in a coordinated manner. Moreover, we can take advantage of the fact that P4-ATPases, like most other P-type ATPases, form an acid-stable phosphorylated intermediate, to verify that the expressed complex is functional.
Collapse
Affiliation(s)
- Hassina Azouaoui
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France
| | - Cédric Montigny
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France
| | - Aurore Jacquot
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France
- UMR 5004, Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes-Claude Grignon, Agro-M/CNRS/INRA/SupAgro/UM2, Montpellier, 34060, France
| | - Raphaëlle Barry
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France
- INSERM, U968, Paris, 75012, France
- UMR_S 968, Institut de la Vision, Sorbonne Universités, UPMC Univ Paris 06, Paris, 75012, France
- CNRS, UMR 7210, Paris, 75012, France
| | - Philippe Champeil
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France
| | - Guillaume Lenoir
- Institute for Integrative Biology of the Cell (I2BC) - UMR 9198 CEA/CNRS/Université Paris-Sud, Gif-sur-Yvette Cedex, 91191, France.
- CEA, iBiTec-S/SB2SM, CEA Saclay, Gif-sur-Yvette, 91191, France.
| |
Collapse
|
31
|
Karlsen JL, Bublitz M. How to Compare, Analyze, and Morph Between Crystal Structures of Different Conformations: The P-Type ATPase Example. Methods Mol Biol 2016; 1377:523-39. [PMID: 26695058 DOI: 10.1007/978-1-4939-3179-8_43] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the past 15 years, a large body of structural information on P-type ATPases has accumulated in the Protein Data Bank. The available crystal structures cover different enzymes in a variety of conformational states that are associated with the enzymatic activity of ATP-dependent ion translocation across membranes. This chapter provides an overview about the available structural information, along with some practical instructions on how to make meaningful comparisons of structures in different conformations, and how to generate morphs between series of structures, in order to analyze domain movements and structural flexibility.
Collapse
Affiliation(s)
- Jesper L Karlsen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus C, 8000, Denmark.
| | - Maike Bublitz
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| |
Collapse
|
32
|
Moerkerke S, Wouters J, Jabin I. Selective Recognition of Phosphatidylcholine Lipids by a Biomimetic Calix[6]tube Receptor. J Org Chem 2015; 80:8720-6. [DOI: 10.1021/acs.joc.5b01531] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Steven Moerkerke
- Laboratoire
de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue
F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
| | - Johan Wouters
- Département
de Chimie, Université de Namur (UNamur), Rue de Bruxelles 61, B-5000 Namur, Belgium
| | - Ivan Jabin
- Laboratoire
de Chimie Organique, Université Libre de Bruxelles (ULB), Avenue
F. D. Roosevelt 50, CP160/06, B-1050 Brussels, Belgium
| |
Collapse
|
33
|
Autzen HE, Siuda I, Sonntag Y, Nissen P, Møller JV, Thøgersen L. Regulation of the Ca(2+)-ATPase by cholesterol: a specific or non-specific effect? Mol Membr Biol 2015; 32:75-87. [PMID: 26260074 DOI: 10.3109/09687688.2015.1073382] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Like other integral membrane proteins, the activity of the Sarco/Endoplasmic Reticulum Ca(2+)-ATPase (SERCA) is regulated by the membrane environment. Cholesterol is present in the endoplasmic reticulum membrane at low levels, and it has the potential to affect SERCA activity both through direct, specific interaction with the protein or through indirect interaction through changes of the overall membrane properties. There are experimental data arguing for both modes of action for a cholesterol-mediated regulation of SERCA. In the current study, coarse-grained molecular dynamics simulations are used to address how a mixed lipid-cholesterol membrane interacts with SERCA. Candidates for direct regulatory sites with specific cholesterol binding modes are extracted from the simulations. The binding pocket for thapsigargin, a nanomolar inhibitor of SERCA, has been suggested as a cholesterol binding site. However, the thapsigargin binding pocket displayed very little cholesterol occupation in the simulations. Neither did atomistic simulations of cholesterol in the thapsigargin binding pocket support any specific interaction. The current study points to a non-specific effect of cholesterol on SERCA activity, and offers an alternative interpretation of the experimental results used to argue for a specific effect.
Collapse
Affiliation(s)
- Henriette Elisabeth Autzen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Iwona Siuda
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,c Bioinformatics Research Centre (BiRC) , Aarhus , Denmark , and
| | - Yonathan Sonntag
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Poul Nissen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,b Department of Molecular Biology and Genetics , Aarhus University , Aarhus , Denmark
| | - Jesper Vuust Møller
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,d Department of Biomedicine , Aarhus University , Aarhus , Denmark
| | - Lea Thøgersen
- a Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation , Aarhus , Denmark .,c Bioinformatics Research Centre (BiRC) , Aarhus , Denmark , and
| |
Collapse
|
34
|
Espinoza-Fonseca LM, Ramírez-Salinas GL. Microsecond Molecular Simulations Reveal a Transient Proton Pathway in the Calcium Pump. J Am Chem Soc 2015; 137:7055-8. [PMID: 26028459 DOI: 10.1021/jacs.5b03814] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The calcium pump sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) counter-transports Ca(2+) and H(+) at the expense of ATP hydrolysis. SERCA uses separate proton and metal ion pathways during active transport to neutralize the highly charged transport site, thus preserving SERCA's structural stability during active Ca(2+) transport. Although separate metal ion and proton pathways have been identified during slow (millisecond) structural transitions of SERCA, the existence of simultaneous metal and proton pathways during fast (microsecond) structural transitions remains unknown. We have analyzed microsecond-long trajectories of E1·H(+)771, a protonated intermediate of the pump populated during SERCA regulation. We found a transiently established hydrophobic pore in the luminal side of the transmembrane helices 6, 8, and 9. This narrow (0.5-0.6 nm) pore connects the transport sites to the sarcoplasmic reticulum lumen through a chain of water molecules. Protein pKa calculations of the transport site residues and structural analysis of the water molecules showed that this pore is suitable for proton transport. This transient proton pathway ensures neutralization of the transport sites during the rapid structural transitions associated with regulation of the pump. We conclude that this transient proton pathway plays a central role in optimizing active Ca(2+) transport by SERCA. Our discovery provides insight into ion-exchange mechanisms through transient hydrophobic pores in P-type ATPases.
Collapse
Affiliation(s)
- L Michel Espinoza-Fonseca
- †Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - G Lizbeth Ramírez-Salinas
- ‡Laboratorio de Modelado Molecular y Bioinformática, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico
| |
Collapse
|
35
|
Huliciak M, Reinhard L, Laursen M, Fedosova N, Nissen P, Kubala M. Crystals of Na+/K+-ATPase with bound cisplatin. Biochem Pharmacol 2014; 92:494-8. [DOI: 10.1016/j.bcp.2014.08.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/25/2014] [Accepted: 08/28/2014] [Indexed: 11/30/2022]
|
36
|
Drachmann ND, Olesen C, Møller JV, Guo Z, Nissen P, Bublitz M. Comparing crystal structures of Ca(2+) -ATPase in the presence of different lipids. FEBS J 2014; 281:4249-62. [PMID: 25103814 DOI: 10.1111/febs.12957] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 08/03/2014] [Accepted: 08/04/2014] [Indexed: 12/01/2022]
Abstract
The activity of the sarco/endoplasmic reticulum Ca(2+) -ATPase (SERCA) depends strongly on the lipid composition of the surrounding membrane. Yet, structural information on SERCA-lipid interaction is still relatively scarce, and the influence of different lipids on the enzyme is not well understood. We have analyzed SERCA crystal structures in the presence of four different phosphatidylcholine lipids of different lengths and double-bond compositions, and we find three different binding sites for lipid head groups, which are apparently independent of the acyl moiety of the lipids used. By comparison with other available SERCA structures with bound lipids, we find a total of five recurring sites, two of which are specific to certain conformational states of the enzyme, two others are state-independent, and one is a crucial site for crystal formation. Three of the binding sites overlap with or are in close vicinity to known binding sites for various SERCA-specific inhibitors and regulators, e.g. thapsigargin, sarcolipin/phospholamban and cyclopiazonic acid. Whereas the transient sites are amenable to a transient, regulatory influence of lipid molecules, the state-independent sites probably provide a flexible anchoring of the protein in the fluid bilayer.
Collapse
Affiliation(s)
- Nikolaj D Drachmann
- Centre for Membrane Pumps in Cells and Disease - PUMPkin, Danish National Research Foundation, Aarhus, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Denmark
| | | | | | | | | | | |
Collapse
|
37
|
Clausen JD, Holdensen AN, Andersen JP. Critical roles of interdomain interactions for modulatory ATP binding to sarcoplasmic reticulum Ca2+-ATPase. J Biol Chem 2014; 289:29123-34. [PMID: 25193668 DOI: 10.1074/jbc.m114.571687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP has dual roles in the reaction cycle of sarcoplasmic reticulum Ca(2+)-ATPase. Upon binding to the Ca2E1 state, ATP phosphorylates the enzyme, and by binding to other conformational states in a non-phosphorylating modulatory mode ATP stimulates the dephosphorylation and other partial reaction steps of the cycle, thereby ensuring a high rate of Ca(2+) transport under physiological conditions. The present study elucidates the mechanism underlying the modulatory effect on dephosphorylation. In the intermediate states of dephosphorylation the A-domain residues Ser(186) and Asp(203) interact with Glu(439) (N-domain) and Arg(678) (P-domain), respectively. Single mutations to these residues abolish the stimulation of dephosphorylation by ATP. The double mutation swapping Asp(203) and Arg(678) rescues ATP stimulation, whereas this is not the case for the double mutation swapping Ser(186) and Glu(439). By taking advantage of the ability of wild type and mutant Ca(2+)-ATPases to form stable complexes with aluminum fluoride (E2·AlF) and beryllium fluoride (E2·BeF) as analogs of the E2·P phosphoryl transition state and E2P ground state, respectively, of the dephosphorylation reaction, the mutational effects on ATP binding to these intermediates are demonstrated. In the wild type Ca(2+)-ATPase, the ATP affinity of the E2·P phosphoryl transition state is higher than that of the E2P ground state, thus explaining the stimulation of dephosphorylation by nucleotide-induced transition state stabilization. We find that the Asp(203)-Arg(678) and Ser(186)-Glu(439) interdomain bonds are critical, because they tighten the interaction with ATP in the E2·P phosphoryl transition state. Moreover, ATP binding and the Ser(186)-Glu(439) bond are mutually exclusive in the E2P ground state.
Collapse
Affiliation(s)
- Johannes D Clausen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark, and the Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Anne Nyholm Holdensen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark, and the Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Jens Peter Andersen
- From the Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark, and
| |
Collapse
|
38
|
Espinoza-Fonseca LM, Autry JM, Thomas DD. Microsecond molecular dynamics simulations of Mg²⁺- and K⁺-bound E1 intermediate states of the calcium pump. PLoS One 2014; 9:e95979. [PMID: 24760008 PMCID: PMC3997511 DOI: 10.1371/journal.pone.0095979] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 03/31/2014] [Indexed: 12/31/2022] Open
Abstract
We have performed microsecond molecular dynamics (MD) simulations to characterize the structural dynamics of cation-bound E1 intermediate states of the calcium pump (sarcoendoplasmic reticulum Ca²⁺-ATPase, SERCA) in atomic detail, including a lipid bilayer with aqueous solution on both sides. X-ray crystallography with 40 mM Mg²⁺ in the absence of Ca²⁺ has shown that SERCA adopts an E1 structure with transmembrane Ca²⁺-binding sites I and II exposed to the cytosol, stabilized by a single Mg²⁺ bound to a hybrid binding site I'. This Mg²⁺-bound E1 intermediate state, designated E1•Mg²⁺, is proposed to constitute a functional SERCA intermediate that catalyzes the transition from E2 to E1•2Ca²⁺ by facilitating H⁺/Ca²⁺ exchange. To test this hypothesis, we performed two independent MD simulations based on the E1•Mg²⁺ crystal structure, starting in the presence or absence of initially-bound Mg²⁺. Both simulations were performed for 1 µs in a solution containing 100 mM K⁺ and 5 mM Mg²⁺ in the absence of Ca²⁺, mimicking muscle cytosol during relaxation. In the presence of initially-bound Mg²⁺, SERCA site I' maintained Mg²⁺ binding during the entire MD trajectory, and the cytosolic headpiece maintained a semi-open structure. In the absence of initially-bound Mg²⁺, two K⁺ ions rapidly bound to sites I and I' and stayed loosely bound during most of the simulation, while the cytosolic headpiece shifted gradually to a more open structure. Thus MD simulations predict that both E1•Mg²⁺ and E•2K+ intermediate states of SERCA are populated in solution in the absence of Ca²⁺, with the more open 2K+-bound state being more abundant at physiological ion concentrations. We propose that the E1•2K⁺ state acts as a functional intermediate that facilitates the E2 to E1•2Ca²⁺ transition through two mechanisms: by pre-organizing transport sites for Ca²⁺ binding, and by partially opening the cytosolic headpiece prior to Ca²⁺ activation of nucleotide binding.
Collapse
Affiliation(s)
- L. Michel Espinoza-Fonseca
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
- * E-mail:
| | - Joseph M. Autry
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - David D. Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| |
Collapse
|
39
|
Li C, Kumar S, Montigny C, le Maire M, Barth A. Quality assessment of recombinant proteins by infrared spectroscopy. Characterisation of a protein aggregation related band of the Ca2+-ATPase. Analyst 2014; 139:4231-40. [DOI: 10.1039/c4an00483c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
FTIR spectroscopy detects aggregates of recombinantly produced protein and can therefore be used for quality control.
Collapse
Affiliation(s)
- Chenge Li
- Department of Biochemistry and Biophysics
- Arrhenius Laboratories
- Stockholm University
- SE-106 91 Stockholm, Sweden
| | - Saroj Kumar
- Department of Biochemistry and Biophysics
- Arrhenius Laboratories
- Stockholm University
- SE-106 91 Stockholm, Sweden
| | | | | | - Andreas Barth
- Department of Biochemistry and Biophysics
- Arrhenius Laboratories
- Stockholm University
- SE-106 91 Stockholm, Sweden
| |
Collapse
|