Identification of two late acyltransferase genes responsible for lipid A biosynthesis in Moraxella catarrhalis.
Lipid A is a biological component of the lipo-oligosaccharide of a human pathogen, Moraxella catarrhalis. No other acyltransferases except for UDP-GlcNAc acyltransferase, responsible for lipid A biosynthesis in M. catarrhalis, have been identified. By bioinformatics, two late acyltransferase genes, lpxX and lpxL, responsible for lipid A biosynthesis were identified, and knockout mutants of each gene in M. catarrhalis strain O35E were constructed and named O35ElpxX and O35ElpxL. Structural analysis of lipid A from the parental strain and derived mutants showed that O35ElpxX lacked two decanoic acids (C10:0), whereas O35ElpxL lacked one dodecanoic (lauric) acid (C12:0), suggesting that lpxX encoded decanoyl transferase and lpxL encoded dodecanoyl transferase. Phenotypic analysis revealed that both mutants were similar to the parental strain in their toxicity in vitro. However, O35ElpxX was sensitive to the bactericidal activity of normal human serum and hydrophobic reagents. It had a reduced growth rate in broth and an accelerated bacterial clearance at 3 h (P < 0.01) or 6 h (P < 0.05) after an aerosol challenge in a murine model of bacterial pulmonary clearance. O35ElpxL presented similar patterns to those of the parental strain, except that it was slightly sensitive to the hydrophobic reagents. These results indicate that these two genes, particularly lpxX, encoding late acyltransferases responsible for incorporation of the acyloxyacyl-linked secondary acyl chains into lipid A, are important for the biological activities of M. catarrhalis.
Gao
Song
S
Vaccine Research Section, National Institute on Deafness and Other Communication Disorders, Rockville, MD 20850, USA.
Peng
Daxin
D
Zhang
Wenhong
W
Muszyński
Artur
A
Carlson
Russell W
RW
Gu
Xin-Xing
XX
D000217:Acyltransferases / Q000235:genetics*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D001769:Blood / Q000382:microbiology; D006801:Humans; D008050:Lipid A / Q000096:biosynthesis* / Q000737:chemistry; D051379:Mice; D008969:Molecular Sequence Data; D001936:Moraxella catarrhalis / Q000201:enzymology / Q000235:genetics*; D009154:Mutation
D001426:Bacterial Proteins; D008050:Lipid A; D000217:Acyltransferases; C118473:LpxL protein, bacteria
Infect Immun. 2001 Oct;69(10):5981-90
11553534
Infect Immun. 2001 Mar;69(3):1358-63
11179299
J Biol Chem. 1997 Apr 18;272(16):10353-60
9099672
J Biol Chem. 1999 Apr 2;274(14):9677-85
10092655
Eur J Biochem. 1999 Oct;265(2):524-9
10504382
Anal Biochem. 1982 Jan 1;119(1):115-9
6176137
Antimicrob Agents Chemother. 1993 Nov;37(11):2255-60
8285603
Carbohydr Res. 1988 Apr 15;175(2):273-82
2900066
J Bacteriol. 2005 May;187(9):2939-47
15838019
Pediatr Infect Dis J. 1994 Jan;13(1 Suppl 1):S23-6; discussion S50-4
8159511
J Biol Chem. 1995 Nov 10;270(45):27151-9
7592970
Nucleic Acids Res. 2004 Jul 1;32(Web Server issue):W321-6
15215403
Annu Rev Biochem. 2007;76:295-329
17362200
Carbohydr Res. 1994 May 5;257(2):269-84
7516823
Infect Immun. 2000 Sep;68(9):4980-5
10948114
J Exp Med. 2000 Mar 20;191(6):949-60
10727457
Infect Immun. 1998 May;66(5):1891-7
9573066
Bioinformatics. 2007 Mar 15;23(6):673-9
17237039
Microb Pathog. 2003 Mar;34(3):121-30
12631473
Infect Immun. 2005 Apr;73(4):2400-10
15784586
Microbes Infect. 2000 Apr;2(5):547-59
10865200
J Clin Microbiol. 1990 Feb;28(2):182-7
2107197
Am J Respir Crit Care Med. 2005 Jul 15;172(2):195-9
15805178
Comput Appl Biosci. 1994 Dec;10(6):685-6
7704669
J Bacteriol. 2006 Feb;188(4):1381-8
16452420
Infect Immun. 1993 May;61(5):2003-10
7683000
Infect Immun. 2003 Feb;71(2):647-55
12540541
Comput Chem. 2001 Dec;26(1):51-6
11765852
J Bacteriol. 1997 Sep;179(17):5521-33
9287009
Glycobiology. 2008 Jun;18(6):447-55
18337458
Infect Immun. 2002 Feb;70(2):909-20
11796626
J Bacteriol. 1999 Feb;181(4):1099-109
9973334
Clin Microbiol Rev. 1990 Oct;3(4):293-320
2121328
J Clin Microbiol. 2005 Dec;43(12):6139-43
16333114
Infect Immun. 1992 Sep;60(9):3824-9
1500191
Microbiol Rev. 1993 Sep;57(3):655-82
7504166
Infect Immun. 2003 Nov;71(11):6426-34
14573664
Microbiol Rev. 1996 Jun;60(2):267-79
8801433
Infect Immun. 2000 Sep;68(9):5261-8
10948153
Annu Rev Biochem. 2002;71:635-700
12045108
J Biol Chem. 1996 May 17;271(20):12095-102
8662613
Plasmid. 2006 Sep;56(2):133-7
16757025
Infect Immun. 2007 Nov;75(11):5518-31
17724076
Infect Immun. 2002 Aug;70(8):4661-8
12117980
Infect Immun. 2003 Sep;71(9):4977-84
12933840
J Bacteriol. 1992 Feb;174(3):702-10
1732206
Infect Immun. 2005 Jul;73(7):4222-30
15972513
Infect Immun. 2005 Nov;73(11):7569-77
16239560
J Bacteriol. 2002 May;184(9):2379-88
11948150
Eur J Biochem. 1994 Feb 15;220(1):209-16
8119289
Clin Microbiol Rev. 2002 Jan;15(1):125-44
11781271
Carbohydr Res. 2006 Nov 6;341(15):2600-6
16934238