5VRH

Apolipoprotein N-acyltransferase C387S active site mutant

Summary for 5VRH

• Entry DOI: 10.2210/pdb5vrh/pdb
• Related: 5VRG
• Descriptor: Apolipoprotein N-acyltransferase, (2S)-2,3-dihydroxypropyl (9Z)-octadec-9-enoate, MAGNESIUM ION, ... (7 entities in total)
• Functional Keywords: lnt c387s, acyl transferase, membrane protein, transferase
• Biological source: Escherichia coli (strain K12)
• Cellular location: Cell inner membrane ; Multi- pass membrane protein : P23930
• Total number of polymer chains: 1
• Total formula weight: 60185.21

Authors

Murray, J.M.,Noland, C.L. (deposition date: 2017-05-10, release date: 2017-07-12, Last modification date: 2023-10-04)

Primary citation

Noland, C.L.,Kattke, M.D.,Diao, J.,Gloor, S.L.,Pantua, H.,Reichelt, M.,Katakam, A.K.,Yan, D.,Kang, J.,Zilberleyb, I.,Xu, M.,Kapadia, S.B.,Murray, J.M.
Structural insights into lipoprotein N-acylation by Escherichia coli apolipoprotein N-acyltransferase.
Proc. Natl. Acad. Sci. U.S.A., 114:E6044-E6053, 2017

PubMed Abstract: Gram-negative bacteria express a diverse array of lipoproteins that are essential for various aspects of cell growth and virulence, including nutrient uptake, signal transduction, adhesion, conjugation, sporulation, and outer membrane protein folding. Lipoprotein maturation requires the sequential activity of three enzymes that are embedded in the cytoplasmic membrane. First, phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) recognizes a conserved lipobox motif within the prolipoprotein signal sequence and catalyzes the addition of diacylglycerol to an invariant cysteine. The signal sequence is then cleaved by signal peptidase II (LspA) to give an N-terminal S-diacylglyceryl cysteine. Finally, apolipoprotein -acyltransferase (Lnt) catalyzes the transfer of the -1-acyl chain of phosphatidylethanolamine to this N-terminal cysteine, generating a mature, triacylated lipoprotein. Although structural studies of Lgt and LspA have yielded significant mechanistic insights into this essential biosynthetic pathway, the structure of Lnt has remained elusive. Here, we present crystal structures of wild-type and an active-site mutant of Lnt. The structures reveal a monomeric eight-transmembrane helix fold that supports a periplasmic carbon-nitrogen hydrolase domain containing a Cys-Glu-Lys catalytic triad. Two lipids are bound at the active site in the structures, and we propose a putative phosphate recognition site where a chloride ion is coordinated near the active site. Based on these structures and complementary cell-based, biochemical, and molecular dynamics approaches, we propose a mechanism for substrate engagement and catalysis by Lnt.

PubMed: 28698362
DOI: 10.1073/pnas.1707813114

Experimental method

X-RAY DIFFRACTION (2.137 Å)