Escherichia coli K-12 substr. MG1655 Enzyme: α-amylase

Gene: malS Accession Numbers: EG11316 (EcoCyc), b3571, ECK3560

Regulation Summary Diagram: ?

Regulation summary diagram for malS

MalS is a periplasmic enzyme that degrades linear dextrins of at least three glucose residues. Cycloheptaose and cyclooctaose can serve as substrates, classifying the enzyme as an α-amylase hydrolyzing internal 1,4-glucosidic linkages [Freundlieb86]. MalS recognizes substrates from the non-reducing end and preferentially liberates maltohexaose [Freundlieb88], which can then be transported through the cytoplasmic membrane via the maltose ABC transporter. MalS is thought to provide a growth advantage by degrading periplasmic maltodextrins between 7 and 15 glucose units in length [Freundlieb86].

MalS is one of two α-amylases present in E. coli. The second enzyme, AmyA, is cytoplasmic.

MalS is a monomer in solution; two intramolecular disulfide bonds have been mapped [Spiess97].

Expression of malS is under the control of the MalT transcriptional activator [Freundlieb86].

Gene Citations: [Schneider92, Otsuka96, Monsieurs05, Bukau86, Wang87]

Locations: periplasmic space

Map Position: [3,735,520 -> 3,737,550] (80.51 centisomes, 290°)
Length: 2031 bp / 676 aa

Molecular Weight of Polypeptide: 75.713 kD (from nucleotide sequence), 66 kD (experimental) [Freundlieb86 ]

pI: 5.67

Unification Links: ASAP:ABE-0011668 , CGSC:17659 , DIP:DIP-10148N , EchoBASE:EB1292 , EcoGene:EG11316 , EcoliWiki:b3571 , Mint:MINT-1293484 , ModBase:P25718 , OU-Microarray:b3571 , PortEco:malS , PR:PRO_000023154 , Pride:P25718 , Protein Model Portal:P25718 , RefSeq:NP_418028 , RegulonDB:EG11316 , SMR:P25718 , String:511145.b3571 , UniProt:P25718

Relationship Links: CAZy:IN-FAMILY:GH13 , InterPro:IN-FAMILY:IPR006047 , InterPro:IN-FAMILY:IPR006589 , InterPro:IN-FAMILY:IPR013781 , InterPro:IN-FAMILY:IPR014635 , InterPro:IN-FAMILY:IPR015902 , InterPro:IN-FAMILY:IPR017853 , Panther:IN-FAMILY:PTHR10357 , Pfam:IN-FAMILY:PF00128 , Smart:IN-FAMILY:SM00642

In Paralogous Gene Group: 123 (6 members)

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Genetic Regulation Schematic: ?

Genetic regulation schematic for malS

GO Terms:

Biological Process: GO:0030980 - alpha-glucan catabolic process Inferred from experiment Inferred by computational analysis [GOA01, Freundlieb86]
GO:0051692 - cellular oligosaccharide catabolic process Inferred from experiment Inferred by computational analysis [GOA01, Freundlieb86]
GO:0005975 - carbohydrate metabolic process Inferred by computational analysis [UniProtGOA11, GOA01]
GO:0008152 - metabolic process Inferred by computational analysis [UniProtGOA11]
Molecular Function: GO:0004556 - alpha-amylase activity Inferred from experiment Inferred by computational analysis [GOA01a, GOA01, Freundlieb86, Spiess97]
GO:0005509 - calcium ion binding Inferred from experiment Inferred by computational analysis [GOA01, Spiess97]
GO:0003824 - catalytic activity Inferred by computational analysis [GOA01]
GO:0016787 - hydrolase activity Inferred by computational analysis [UniProtGOA11]
GO:0016798 - hydrolase activity, acting on glycosyl bonds Inferred by computational analysis [UniProtGOA11]
GO:0043169 - cation binding Inferred by computational analysis [GOA01]
GO:0046872 - metal ion binding Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0030288 - outer membrane-bounded periplasmic space Inferred from experiment Inferred by computational analysis [DiazMejia09, Han14, Freundlieb86]
GO:0042597 - periplasmic space Inferred from experiment Inferred by computational analysis [UniProtGOA11a, UniProtGOA11, GOA01, Freundlieb86]

MultiFun Terms: metabolism carbon utilization carbon compounds
metabolism degradation of macromolecules polysaccharides

Essentiality data for malS knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Last-Curated ? 30-Mar-2011 by Keseler I , SRI International

Enzymatic reaction of: α-amylase

Synonyms: 1,4-α-D-glucan glucanohydrolase

a 1,4-α-D-glucan[periplasmic space] + n H2O[periplasmic space] <=> a 1,4-α-D-glucan[periplasmic space] + maltohexaose[periplasmic space]

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

Alternative Substrates [Comment 5]:

The Km for PG6 (a maltohexaose) is 3 µM [Freundlieb88], and the Km for p-nitrophenylhexaoside is 49 µM [Spiess97].

Cofactors or Prosthetic Groups: Ca2+ [Spiess97]

pH(opt): 8-8.5 [Spiess97]

Sequence Features

Protein sequence of alpha-amylase with features indicated

Feature Class Location Citations Comment
Signal-Sequence 1 -> 17
[Schneider92, UniProt11]
Chain 18 -> 676
UniProt: Alpha-amylase;
Intrachain-Disulfide-Bond 57, 75
Intrachain-Disulfide-Bond 121, 537
Metal-Binding-Site 314
UniProt: Calcium; Non-Experimental Qualifier: by similarity;
Active-Site 460
UniProt: Nucleophile; Non-Experimental Qualifier: by similarity;
Metal-Binding-Site 464
UniProt: Calcium; via carbonyl oxygen; Non-Experimental Qualifier: by similarity;
Active-Site 503
UniProt: Proton donor; Non-Experimental Qualifier: by similarity;
Active-Site 565
UniProt: Non-Experimental Qualifier: by similarity;

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Unit:

Transcription-unit diagram


10/20/97 Gene b3571 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11316; confirmed by SwissProt match.


Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

Bukau86: Bukau B, Ehrmann M, Boos W (1986). "Osmoregulation of the maltose regulon in Escherichia coli." J Bacteriol 166(3);884-91. PMID: 2423504

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Freundlieb86: Freundlieb S, Boos W (1986). "Alpha-amylase of Escherichia coli, mapping and cloning of the structural gene, malS, and identification of its product as a periplasmic protein." J Biol Chem 1986;261(6);2946-53. PMID: 3005273

Freundlieb88: Freundlieb S, Ehmann U, Boos W (1988). "Facilitated diffusion of p-nitrophenyl-alpha-D-maltohexaoside through the outer membrane of Escherichia coli. Characterization of LamB as a specific and saturable channel for maltooligosaccharides." J Biol Chem 263(1);314-20. PMID: 3275641

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

Han14: Han MJ, Kim JY, Kim JA (2014). "Comparison of the large-scale periplasmic proteomes of the Escherichia coli K-12 and B strains." J Biosci Bioeng 117(4);437-42. PMID: 24140104

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Monsieurs05: Monsieurs P, De Keersmaecker S, Navarre WW, Bader MW, De Smet F, McClelland M, Fang FC, De Moor B, Vanderleyden J, Marchal K (2005). "Comparison of the PhoPQ regulon in Escherichia coli and Salmonella typhimurium." J Mol Evol 60(4);462-74. PMID: 15883881

Otsuka96: Otsuka J, Watanabe H, Mori KT (1996). "Evolution of transcriptional regulation system through promiscuous coupling of regulatory proteins with operons; suggestion from protein sequence similarities in Escherichia coli." J Theor Biol 1996;178(2);183-204. PMID: 8729576

Schneider92: Schneider E, Freundlieb S, Tapio S, Boos W (1992). "Molecular characterization of the MalT-dependent periplasmic alpha-amylase of Escherichia coli encoded by malS." J Biol Chem 1992;267(8);5148-54. PMID: 1544897

Spiess97: Spiess C, Happersberger HP, Glocker MO, Spiess E, Rippe K, Ehrmann M (1997). "Biochemical characterization and mass spectrometric disulfide bond mapping of periplasmic alpha-amylase MalS of Escherichia coli." J Biol Chem 272(35);22125-33. PMID: 9268356

UniProt09: UniProt Consortium (2009). "UniProt version 15.8 released on 2009-10-01 00:00:00." Database.

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt11: UniProt Consortium (2011). "UniProt version 2011-06 released on 2011-06-30 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

Wang87: Wang MD, Liu L, Wang BM, Berg CM (1987). "Cloning and characterization of the Escherichia coli K-12 alanine-valine transaminase (avtA) gene." J Bacteriol 1987;169(9);4228-34. PMID: 3040683

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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