scholarly journals Transmembrane folding of the human erythrocyte anion exchanger (AE1, Band 3) determined by scanning and insertional N-glycosylation mutagenesis

1999 ◽  
Vol 339 (2) ◽  
pp. 269-279 ◽  
Author(s):  
Milka POPOV ◽  
Jing LI ◽  
Reinhart A. F. REITHMEIER
Keyword(s):  
Anion Exchanger ◽  
Human Erythrocyte ◽  
Band 3 ◽  
Translation System ◽  
Acceptor Site ◽  
Oligosaccharide Structure ◽  
Hek 293 ◽  
Transmembrane Segments ◽  
Free Translation ◽  
A Cell

The human erythrocyte anion exchanger (AE1, Band 3) contains up to 14 transmembrane segments, with a single site of N-glycosylation at Asn642 in extracellular (EC) loop 4. Scanning and insertional N-glycosylation mutagenesis were used to determine the folding pattern of AE1 in the membrane. Full-length AE1, when expressed in transfected human embryonic kidney (HEK)-293 or COS-7 cells, retained a high-mannose oligosaccharide structure. Scanning N-glycosylation mutagenesis of EC loop 4 showed that N-glycosylation acceptor sites (Asn-Xaa-Ser/Thr) spaced 12 residues from the ends of adjacent transmembrane segments could be N-glycosylated. An acceptor site introduced at position 743 in intracellular (IC) loop 5 that could be N-glycosylated in a cell-free translation system was not N-glycosylated in transfected cells. Mutations designed to disrupt the folding of this loop enhanced the level of N-glycosylation at Asn743in vitro. The results suggest that this loop might be transiently exposed to the lumen of the endoplasmic reticulum during biosynthesis but normally folds rapidly, precluding N-glycosylation. EC loop 4 insertions into positions 428, 484, 754 and 854 in EC loops 1, 2, 6 and 7 respectively were efficiently N-glycosylated, showing that these regions were extracellular. EC loop 4 insertions into positions 731 or 785 were poorly N-glycosylated, which was inconsistent with an extracellular disposition for these regions of AE1. Insertion of EC loop 4 into positions 599 and 820 in IC loops 3 and 6 respectively were not N-glycosylated in cells, which was consistent with a cytosolic disposition for these loops. Inhibitor-affinity chromatography with 4-acetamido-4´-isothiocyanostilbene-2,2´-disulphonate (SITS)-Affi-Gel was used to assess whether the AE1 mutants were in a native state. Mutants with insertions at positions 428, 484, 599, 731 and 785 showed impaired inhibitor binding, whereas insertions at positions 754, 820 and 854 retained binding. The results indicate that the folding of the C-terminal region of AE1 is more complex than originally proposed and that this region of the transporter might have a dynamic aspect.

scholarly journals Glycosylation of multiple extracytosolic loops in Band 3, a model polytopic membrane protein

1996 ◽  
Vol 318 (2) ◽  
pp. 645-648 ◽  
Author(s):  
Lisa Y TAM ◽  
Carolina LANDOLT-MARTICORENA ◽  
Reinhart A. F. REITHMEIER
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Band 3 ◽  
Site Directed Mutagenesis ◽  
Acceptor Site ◽  
Oligosaccharyl Transferase ◽  
Transmembrane Segments ◽  
Free Translation ◽  
Reticulocyte Lysates ◽  
Polytopic Membrane Protein

N-glycosylated sites in polytopic membrane proteins are usually localized to single extracytosolic (EC) loops containing more than 30 residues [Landolt-Marticorena and Reithmeier (1994) Biochem. J. 302, 253–260]. This may be due to a biosynthetic restriction whereby only a single loop of nascent polypeptide is available to the oligosaccharyl transferase in the lumen of the endoplasmic reticulum. To test this hypothesis, two types of N-glycosylation mutants were constructed using Band 3, a polytopic membrane protein that contains up to 14 transmembrane segments and a single endogenous site of N-glycosylation at Asn-642 in EC loop 4. In the first set of mutants, an additional N-glycosylation acceptor site (Asn-Xaa-Ser/Thr) was constructed by site-directed mutagenesis in EC loop 3, with or without retention of the endogenous site. In the second set of mutants, EC loop 4 was duplicated and inserted into EC loop 2, again with or without retention of the endogenous site. Cell-free translation experiments using reticulocyte lysates showed that microsomes were able to N-glycosylate multiple EC loops in these Band 3 mutants. The acceptor site in EC loop 3 was poorly N-glycosylated, probably due to the suboptimal size (25 residues) of this EC loop. The localization of N-glycosylation sites to single EC loops in multi-span membrane proteins is probably due to the absence of suitably positioned acceptor sites on multiple loops.

Structural and functional consequences of an N-glycosylation mutation (HEMPAS) affecting human erythrocyte membrane glycoproteins

1998 ◽  
Vol 76 (5) ◽  
pp. 823-835 ◽  
Author(s):  
Homa Kameh ◽  
Carolina Landolt-Marticorena ◽  
Jeffrey HM Charuk ◽  
Harry Schachter ◽  
Reinhart AF Reithmeier
Keyword(s):  
Erythrocyte Membrane ◽  
Anion Exchanger ◽  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Lectin Binding ◽  
Genetic Defect ◽  
Band 3 ◽  
Lymphoid Cells ◽  
Detergent Solution ◽  
Oligosaccharide Structure

Band 3, the human erythrocyte anion exchanger (AE1), and the glucose transporter (GLUT1) proteins each contain a single site of N-glycosylation that is heterogeneously glycosylated. Lectin binding and enzymatic deglycosylation assays showed that the polylactosaminyl oligosaccharide structure of these glycoproteins was altered to a high mannose or hybrid glycan form in three patients with hereditary erythroblastic multinuclearity, with a positive acidified-serum lysis test (HEMPAS). Offspring from one of the HEMPAS patients had intermediate levels of polylactosaminyl oligosaccharide associated with AE1 and GLUT1, suggesting they may have been heterozygous for the genetic defect. The array of polylactosaminyl-containing glycoproteins present in EBV-transformed lymphoblasts derived from fresh blood of HEMPAS patients was similar to control lymphoblasts. HEMPAS lymphoblasts do not therefore express the defect in polylactosamine synthesis found in erythroid cells, indicating that lymphoid cells are not deficient in the processing enzymes or contain an alternative oligosaccharide processing pathway. Purified HEMPAS band 3 had an unaltered oligomeric structure but dimers aggregated more rapidly in detergent solution than normal band 3. The altered oligosaccharide structure did not affect the sensitivity of band 3 to proteolytic digestion in intact red cells but a greater amount of HEMPAS band 3 was associated with the cytoskeleton. The transport activities of AE1 and GLUT1 in HEMPAS erythrocytes were similar to those in normal controls. This shows that the HEMPAS glycosylation defect does not impair the functional accumulation of these two important erythrocyte membrane transporters even though it produces subtle structural changes in band 3 that result in its increased cytoskeletal interaction and self association in detergent solution.Key words: anion exchanger, band 3, erythrocyte, glycoprotein, HEMPAS.

scholarly journals The 3' untranslated region of satellite tobacco necrosis virus RNA stimulates translation in vitro.

1993 ◽  
Vol 13 (6) ◽  
pp. 3340-3349 ◽  
Author(s):  
X Danthinne ◽  
J Seurinck ◽  
F Meulewaeter ◽  
M Van Montagu ◽  
M Cornelissen
Keyword(s):  
Tobacco Necrosis Virus ◽  
Translation System ◽  
Coding Region ◽  
Necrosis Virus ◽  
Untranslated Sequence ◽  
Virus Rna ◽  
Free Translation ◽  
Order Of Magnitude ◽  
A Cell

The RNA of satellite tobacco necrosis virus (STNV) is a monocistronic messenger that lacks both a 5' cap structure and a 3' poly(A) tail. We show that in a cell-free translation system derived from wheat germ, STNV RNA lacking the 600-nucleotide trailer is translated an order of magnitude less efficiently than full-size RNA. Deletion analyses positioned the translational enhancer domain (TED) within a conserved hairpin structure immediately downstream from the coat protein cistron. TED enhances translation when fused to a heterologous mRNA, but the level of enhancement depends on the nature of the 5' untranslated sequence and is maximal in combination with the STNV leader. The STNV leader and TED have two regions of complementarity. One of the complementary regions in TED resembles picornavirus box A, which is involved in cap-independent translation but which is located upstream of the coding region.

scholarly journals A murine fer testis-specific transcript (ferT) encodes a truncated Fer protein.

1990 ◽  
Vol 10 (1) ◽  
pp. 146-153 ◽  
Author(s):  
K Fischman ◽  
J C Edman ◽  
G M Shackleford ◽  
J A Turner ◽  
W J Rutter ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Translation System ◽  
Appearance Time ◽  
Acid Protein ◽  
Mouse Tissues ◽  
Free Translation ◽  
Alternatively Spliced ◽  
A Cell ◽  
Testis Cdna ◽  
Carboxy Terminal

A cDNA for a potential tyrosine kinase-encoding mRNA was isolated from a mouse testis cDNA library. In a survey of eight mouse tissues, a transcript of 2.4 kilobases restricted to testis tissue was found. The mRNA encodes a 453-amino-acid protein of 51,383 daltons, the smallest tyrosine kinase protein ever described. RNA synthesized from the cDNA template directs the synthesis of a 51,000-Mr protein in a cell-free translation system. The carboxy-terminal 409 amino acids are 98 and 90% identical to the carboxy halves of the rat and human Fer proteins, respectively. This suggests that the cDNA represents an alternatively spliced testis-specific fer mRNA and is therefore termed by us ferT. On the basis of the appearance time of the fer mRNA in the testis of maturing neonatal mice, we speculate on the role played by this protein in the development of this organ.

scholarly journals Chemical aminoacylation of tRNAs with fluorinated amino acids for in vitro protein mutagenesis

2010 ◽  
Vol 6 ◽  
Author(s):  
Shijie Ye ◽  
Allison Ann Berger ◽  
Dominique Petzold ◽  
Oliver Reimann ◽  
Benjamin Matt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Translation System ◽  
Biologically Relevant ◽  
Fluorinated Amino Acids ◽  
Free Translation ◽  
Trna Species ◽  
A Cell ◽  
Protein Environment ◽  
Vitro Protein

This article describes the chemical aminoacylation of the yeast phenylalanine suppressor tRNA with a series of amino acids bearing fluorinated side chains via the hybrid dinucleotide pdCpA and ligation to the corresponding truncated tRNA species. Aminoacyl-tRNAs can be used to synthesize biologically relevant proteins which contain fluorinated amino acids at specific sites by means of a cell-free translation system. Such engineered proteins are expected to contribute to our understanding of discrete fluorines’ interaction with canonical amino acids in a native protein environment and to enable the design of fluorinated proteins with arbitrary desired properties.

scholarly journals Three-dimensional map of the dimeric membrane domain of the human erythrocyte anion exchanger, Band 3.

1994 ◽  
Vol 13 (14) ◽  
pp. 3230-3235 ◽  
Author(s):  
D.N. Wang ◽  
V.E. Sarabia ◽  
R.A. Reithmeier ◽  
W. Kühlbrandt
Keyword(s):  
Anion Exchanger ◽  
Human Erythrocyte ◽  
Three Dimensional ◽  
Band 3 ◽  
Membrane Domain

scholarly journals Crystal structure of the anion exchanger domain of human erythrocyte band 3

Science ◽  
2015 ◽  
Vol 350 (6261) ◽  
pp. 680-684 ◽  
Author(s):  
T. Arakawa ◽  
T. Kobayashi-Yurugi ◽  
Y. Alguel ◽  
H. Iwanari ◽  
H. Hatae ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Anion Exchanger ◽  
Human Erythrocyte ◽  
Band 3

Studies of the Biosynthesis of Renin with a Cell-Free Translation System

1981 ◽  
Vol 61 (s7) ◽  
pp. 241s-243s ◽  
Author(s):  
V. J. Dzau ◽  
A. Ouellette ◽  
R. Pratt
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Submaxillary Gland ◽  
Translation System ◽  
Mouse Submaxillary Gland ◽  
Free Translation ◽  
Renin Mrna ◽  
A Cell ◽  
Deficient Mice ◽  
Identical Fashion

1. Poly(A)+ mRNA from mouse submaxillary gland encodes a polypeptide of molecular weight 48 000 (48K polypeptide) which is abundant in the male. 2. This polypeptide is selectively absent in the translation products of mRNA from a strain of genetically renin-deficient mice C57 BL/10J. 3. The 48K polypeptide binds and co-elutes in identical fashion with pure authentic renin on pepstatin affinity chromatography. 4. Immunoprecipitation of translation products of male glandular mRNA with renin-specific antibody yielded this 48K band upon analysis by SDS/polyacrylamide gel electrophoresis and fluorography. Pure renin of molecular weight 37 000 blocked the binding of this polypeptide to antirenin antibody. 5. Mouse submaxillary gland synthesizes a renin precursor. The renin mRNA is androgenically regulated.

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