scholarly journals A super-secondary structure predicted to be common to several α-1,4-d-glucan-cleaving enzymes

1989 ◽  
Vol 259 (1) ◽  
pp. 145-152 ◽  
Author(s):  
E A MacGregor ◽  
B Svensson

Predictions of protein secondary structure are used with amino acid sequence alignments to show that the N-terminal domains of cyclodextrin glucanotransferases and a yeast alpha-glucosidase may have the same super-secondary structure as alpha-amylases, i.e. an (alpha/beta)8-barrel fold. Sequence similarities provide evidence that glucanotransferases, and possibly the glucosidase, are, like alpha-amylases, Ca2+-containing enzymes. The relationship between substrate specificity and the nature of the amino acid residues proposed at the active site is discussed for the transferases and alpha-glucosidase. A set of three programs for an Apple IIe computer to carry out the calculations described by Garnier, Osguthorpe & Robson [(1978) J. Mol. Biol. 120, 97-120] and a set of four programs for an Apple IIe computer to carry out the calculations described by Levin, Robson & Garnier [(1986) FEBS Lett. 205, 303-308] have been deposited as Supplementary Publication SUP 50149 (25 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1989) 257, 5.

2021 ◽  
Vol 12 ◽  
Author(s):  
Sergio Diez-Hermano ◽  
Maria D. Ganfornina ◽  
Arne Skerra ◽  
Gabriel Gutiérrez ◽  
Diego Sanchez

The protein family of Lipocalins is ubiquitously present throughout the tree of life, with the exception of the phylum Archaea. Phylogenetic relationships of chordate Lipocalins have been proposed in the past based on protein sequence similarities, but their highly divergent primary structures and a shortage of experimental annotations in genome projects have precluded a well-supported hypothesis for their evolution. In this work we propose a novel topology for the phylogenetic tree of chordate Lipocalins, inferred from multiple amino acid sequence alignments. Sixteen jawed vertebrates with fair coverage by genomic sequencing were compared. The selected species span an evolutionary range of ∼400 million years, allowing for a balanced representation of all major vertebrate clades. A consensus phylogenetic tree is proposed following a comparison of sequence-based maximum-likelihood trees and protein structure dendrograms. This new phylogeny suggests an APOD-like common ancestor in early chordates, which gave rise, via whole-genome or tandem duplications, to the six Lipocalins currently present in fish (APOD, RBP4, PTGDS, AMBP, C8G, and APOM). Further gene duplications of APOM and PTGDS resulted in the altogether 15 Lipocalins found in contemporary mammals. Insights into the functional impact of relevant amino acid residues in early diverging Lipocalins are also discussed. These results should foster the experimental exploration of novel functions alongside the identification of new members of the Lipocalin family.


2006 ◽  
Vol 34 (1) ◽  
pp. 118-121 ◽  
Author(s):  
E.J. Dridge ◽  
D.J. Richardson ◽  
R.J. Lewis ◽  
C.S. Butler

The AF0174–AF0176 gene cluster in Archaeoglobus fulgidus encodes a putative oxyanion reductase of the D-type (Type II) family of molybdo-enzymes. Sequence analysis reveals that the catalytic subunit AF0176 shares low identity (31–32%) and similarity (41–42%) to both NarG and SerA, the catalytic components of the respiratory nitrate and selenate reductases respectively. Consequently, predicting the oxyanion substrate selectivity of AF0176 has proved difficult based solely on sequence alignments. In the present study, we have modelled both AF0176 and SerA on the recently determined X-ray structure of the NAR (nitrate reductase) from Escherichia coli and have identified a number of key amino acid residues, conserved in all known NAR sequences, including AF0176, that we speculate may enhance selectivity towards trigonal planar (NO3−) rather than tetrahedral (SeO42− and ClO4−) substrates.


1987 ◽  
Vol 248 (3) ◽  
pp. 933-936 ◽  
Author(s):  
I Sakai ◽  
F S Sharief ◽  
Y C Pan ◽  
S S Li

Human lactate dehydrogenase B (LDH-B) cDNA was isolated and sequenced. The LDH-B cDNA insert consists of the protein-coding sequence (999 bp), the 5′ (54 bp) and 3′ (203 bp) non-coding regions, and the poly(A) tail (50 bp). The predicted sequence of 333 amino acid residues was confirmed by amino acid composition and/or sequence analyses of a total of 185 (56%) residues from tryptic peptides of human LDH-B protein. The nucleotide and amino acid sequences of the human LDH-B coding region show 68% and 75% homologies respectively with those of the human LDH-A. The peptide map and amino acid composition data have been deposited as Supplementary Publication SUP 50139 (7 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies are available on prepayment [see Biochem. J. (1987) 241, 5].


1996 ◽  
Vol 318 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Roberto A GEREMIA ◽  
E Alejandro PETRONI ◽  
Luis IELPI ◽  
Bernard HENRISSAT

A number of genes encoding bacterial glycosyltransferases have been sequenced during the last few years, but their low sequence similarity has prevented a straightforward grouping of these enzymes into families. The sequences of several bacterial α-mannosyltransferases have been compared using current alignment algorithms as well as hydrophobic cluster analysis (HCA). These sequences show a similarity which is significant but too low to be reliably aligned using automatic alignment methods. However, a region spanning approx. 270 residues in these proteins could be aligned by HCA, and several invariant amino acid residues were identified. These features were also found in several other glycosyltransferases, as well as in proteins of unknown function present in sequence databases. This similarity most probably reflects the existence of a family of proteins with conserved structural and mechanistic features. It is argued that the present IUBMB classification of glycosyltransferases could be complemented by a classification of these enzymes based on sequence similarities analogous to that which we proposed for glycosyl hydrolases [Henrissat, B. (1991) Biochem. J. 280, 309–316].


1989 ◽  
Vol 264 (2) ◽  
pp. 437-445 ◽  
Author(s):  
J D Hayes ◽  
L A Kerr ◽  
A D Cronshaw

The Alpha class glutathione S-transferases (GSTs) in human liver are composed of polypeptides of Mr 25,900. These enzymes are dimeric, and two immunochemically distinct subunits, B1 and B2, have been described that combine to form GSTs B1B1, B1B2 and B2B2 [Stockman, Beckett & Hayes (1985) Biochem. J. 227, 457-465]. Gradient affinity elution from GSH-Sepharose has been used to resolve the three Alpha class GSTs, and this method has been applied to demonstrate marked inter-individual differences in the hepatic content of GSTs B1B1, B1B2 and B2B2. The B1 and B2 subunits can be resolved by reverse-phase h.p.l.c., and their elution positions suggest that they are equivalent to the alpha chi and alpha y h.p.l.c. peaks described by Ketterer and his colleagues [Ostlund Farrants, Meyer, Coles, Southan, Aitken, Johnson & Ketterer (1987) Biochem. J. 245, 423-428]. The B1 and B2 subunits have now been cleaved with CNBr and the fragments subjected to automated amino acid sequence analysis. The sequence data show that B1 and B2 subunits do not arise from post-translational modification, as had been previously believed for the hepatic Alpha class GSTs, but are instead the products of separate genes; B1 and B2 subunits were found to contain different amino acid residues at positions 88, 110, 111, 112, 116, 124 and 127. The relationship between the B1 and B2 subunits and the cloned GTH1 and GTH2 cDNA sequences [Rhoads, Zarlengo & Tu (1987) Biochem. Biophys. Res. Commun. 145, 474-481] is discussed.


Sign in / Sign up

Export Citation Format

Share Document