共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Boisramé J.-M. Beckerich C. Gaillardin 《Molecular genetics and genomics : MGG》1999,261(4-5):601-609
In an attempt to identify proteins involved in the translocation step of protein secretion, a genetic screen was carried out in the yeast Yarrowia lipolytica. A?conditional lethal mutant which has a defect in the 7S RNA of the signal recognition particle was mutagenized and screened for second-site mutations that specifically exacerbate its temperature sensitivity. This approach had previously allowed the characterization of an endoplasmic reticulum component, Sls1p, involved in protein translocation. A second mutation, sls2-1, was isolated that causes synthetic lethality when combined with the 7S RNA mutation. On its own, the sls2-1 mutation confers a temperature-sensitive growth phenotype. The secretory phenotype of the sls2 mutant consists in abnormal secretion of several polypeptides, and thus differs from the defect in secretory protein synthesis associated with the 7S RNA and sls1-1 mutations. Two new Y. lipolytica genes were identified which can relieve the growth defect of sls2-1 cells: SLS2 itself and SSL2, a multicopy suppressor of the temperature sensitivity of the sls2 mutant. The SLS2 gene encodes a polypeptide that can potentially be farnesylated and phosphorylated, and shares some homology with an S. cerevisiae protein of unknown function. Ssl2p resembles calmodulin-dependent serine/threonine protein kinases. These two proteins may interact to regulate protein sorting. 相似文献
2.
S. J. Hong Y. S. Yi S. S. Koh O. K. Park H. S. Kang 《Molecular & general genetics : MGG》1998,259(4):404-413
The small GTPase Ran is essential for nucleocytoplasmic transport of macromolecules. In the yeast Saccharomyces cerevisiae, Rna1p functions as a Ran-GTPase activating protein (RanGAP1). Strains carrying the rna1-1 mutation exhibit defects in nuclear transport and, as a consequence, accumulate precursor tRNAs. We have isolated two recessive
suppressors of the rna1-1 mutation. Further characterization of one of the suppressor mutations, srn10-1, reveals that the mutation (i) can not bypass the need for Rna1p function and (ii) suppresses the accumulation of unspliced
pre-tRNA caused by rna1-1. The SRN10 gene is not essential for cell viability and encodes an acidic protein (pI = 5.27) of 24.8 kDa. Srn10p is located in the
cytoplasm, as determined by indirect immunofluorescence microscopy. Two-hybrid analysis reveals that there is a physical interaction
between Srn10p and Rna1p in vivo. Our results identify a protein that interacts with the yeast RanGAP1.
Received: 2 March 1998 / Accepted: 17 June 1998 相似文献
3.
Liu DQ Ge JW Qiao XY Jiang YP Liu SM Li YJ 《Applied microbiology and biotechnology》2012,93(6):2437-2446
To develop effective mucosal vaccine formulation against porcine epidemic diarrhea virus (PEDV) infection, the DNA fragments
encoding spike protein immunodominant region S1 and nucleocapsid N of PEDV were inserted into pPG1 (surface-displayed) or
pPG2 (secretory) plasmids followed by electrotransformation into Lactobacillus casei (Lc) to yield four recombinant strains: PG1-S1, PG2-S1, PG1-N, and PG2-N. After intragastric administration, it was observed
that live Lc-expressing S1 protein combined with Lc-expressing N protein could elicit much more potent mucosal and systemic immune responses than the former alone (P < 0.001), however slightly inferior to the latter alone (P > 0.05). Furthermore, the surface-displayed mixture (PG1-S1+ PG1-N) revealed stronger immunogenicity than the secretory mixture
(PG2-S1+ PG2-N) as well as PEDV-neutralizing potency in vitro (P < 0.001). On 49th day after the last immunization, splenocytes were prepared from mice immunized with surface-displayed mixture,
secretory mixture and negative control to be stimulated by purified N and S protein, respectively. The results of ELISA analysis
showed that N protein was capable of inducing a higher level of IL-4 (P < 0.001) and IFN-γ (P < 0.001) than S1 protein in the immunized mice. Taken together, Lc-expressed N protein as molecular adjuvant or immunoenhancer
was able to effectively facilitate the induction of mucosal and systemic immune responses by Lc-expressing S1 region. 相似文献
4.
The 19S regulatory particle of the yeast 26S proteasome consists of six related ATPases (Rpt proteins) and at least 11 non-ATPase
proteins (Rpn proteins). RPN12 (formerly NIN1) encodes an Rpn component of the 19S regulatory particle and is essential for growth. To determine which subunit(s) of the
26S proteasome interact(s) with Rpn12, we attempted to screen for mutations that cause synthetic lethality in the presence
of the rpn12-1 (formerly nin1-1) mutation. Among the candidates recovered was a new allele of RPT1 (formerly CIM5). This mutant allele was designated rpt1-2; on its own this mutation caused no phenotypic change, whereas the rpn12-1 rpt1-2 double mutant was lethal, suggesting a strong interaction between Rpn12 and Rpt1. The site of the rpt1-2 mutation was determined by DNA sequencing of the RPT1 locus retrieved from the mutant, and a single nucleotide alteration was found. This changes amino acid 446 of the RPT1 product from alanine to valine. The alanine residue is conserved in all Rpt proteins, except Rpt5, but no function has yet
been assigned to the region that contains it. We propose that this region is necessary for Rpt1 to interact with Rpn12. The
terminal phenotype of the rpn12-1 rpt1-2 double mutant was not cell cycle specific, suggesting that in the double mutant cells the function of the 26S proteasome
is completely eliminated, thereby inducing multiple defects in cellular functions.
Received: 1 February 1999 / Accepted: 5 May 1999 相似文献
5.
Boisramé A Chasles M Babour A Beckerich JM 《Molecular genetics and genomics : MGG》2006,275(3):242-250
The endoplasmic reticulum associated degradation (ERAD) is a process widespread in eukaryotes that enable cells to get rid
of unfolded or unassembled polypeptides which jam the endoplasmic reticulum compartment. In order to improve understanding
of the initial steps of the secretory pathway and their relationship, we focused on components of the ERAD ubiquitylation
machinery in the yeast Yarrowia lipolytica. Two Hrd1p homologues, Hrd1p and Hrh1p, were identified in Y. lipolytica. A study of the fate of the heterologous CPY* reporter protein showed that YlHrd1p is involved in the elimination of this
misfolded polypeptide, while YlHrh1p is not. Moreover, the different phenotypic pattern displayed by Δhrd1 and Δhrh1 cells suggests that the two putative E3 enzymes function in separate ways. Our results bring some evidence of a coupling
between the ERAD pathway and the co-translational translocation process and show that studies in Y. lipolytica can give new insights into events that take place in the ER. 相似文献
6.
Sanni P. Voutilainen Harry Boer Marika Alapuranen Janne J?nis Jari Vehmaanper? Anu Koivula 《Applied microbiology and biotechnology》2009,83(2):261-272
Two different types of approach were taken to improve the hydrolytic activity towards crystalline cellulose at elevated temperatures
of Melanocarpus albomyces Cel7B (Ma Cel7B), a single-module GH-7 family cellobiohydrolase. Structure-guided protein engineering was used to introduce an additional
tenth disulphide bridge to the Ma Cel7B catalytic module. In addition, a fusion protein was constructed by linking a cellulose-binding module (CBM) and a linker
from the Trichoderma reesei Cel7A to the C terminus of Ma Cel7B. Both approaches proved successful. The disulphide bridge mutation G4C/M70C located near the N terminus, close to the
entrance of the active site tunnel of Ma Cel7B, led to improved thermostability (ΔT
m = 2.5°C). By adding the earlier found thermostability-increasing mutation S290T (ΔT
m = 1.5°C) together with the disulphide bridge mutation, the unfolding temperature was increased by 4°C (mutant G4C/M70C/S290T)
compared to that of the wild-type enzyme, thus showing an additive effect on thermostability. Both disulphide mutants had
increased activity towards microcrystalline cellulose (Avicel) at 75°C, apparently solely because of their improved thermostability.
The addition of a CBM also improved the thermostability (ΔT
m = 2.5°C) and caused a clear (sevenfold) increase in the hydrolysis activity of Ma Cel7B towards Avicel at 70°C. 相似文献
7.
Engineering of the Yeast Yarrowia lipolytica for the Production of Glycoproteins Lacking the Outer-Chain Mannose Residues of N-Glycans
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yunkyoung Song Min Hee Choi Jeong-Nam Park Moo Woong Kim Eun Jung Kim Hyun Ah Kang Jeong-Yoon Kim 《Applied microbiology》2007,73(14):4446-4454
In an attempt to engineer a Yarrowia lipolytica strain to produce glycoproteins lacking the outer-chain mannose residues of N-linked oligosaccharides, we investigated the functions of the OCH1 gene encoding a putative α-1,6-mannosyltransferase in Y. lipolytica. The complementation of the Saccharomyces cerevisiae och1 mutation by the expression of YlOCH1 and the lack of in vitro α-1,6-mannosyltransferase activity in the Yloch1 null mutant indicated that YlOCH1 is a functional ortholog of S. cerevisiae OCH1. The oligosaccharides assembled on two secretory glycoproteins, the Trichoderma reesei endoglucanase I and the endogenous Y. lipolytica lipase, from the Yloch1 null mutant contained a single predominant species, the core oligosaccharide Man8GlcNAc2, whereas those from the wild-type strain consisted of oligosaccharides with heterogeneous sizes, Man8GlcNAc2 to Man12GlcNAc2. Digestion with α-1,2- and α-1,6-mannosidase of the oligosaccharides from the wild-type and Yloch1 mutant strains strongly supported the possibility that the Yloch1 mutant strain has a defect in adding the first α-1,6-linked mannose to the core oligosaccharide. Taken together, these results indicate that YlOCH1 plays a key role in the outer-chain mannosylation of N-linked oligosaccharides in Y. lipolytica. Therefore, the Yloch1 mutant strain can be used as a host to produce glycoproteins lacking the outer-chain mannoses and further developed for the production of therapeutic glycoproteins containing human-compatible oligosaccharides. 相似文献
8.
N. Hayashi H. Seino K. Irie M. Watanabe K. L. Clark K. Matsumoto T. Nishimoto 《Molecular & general genetics : MGG》1996,253(1-2):149-156
The Saccharomyces cerevisiae temperature-sensitive mutants srm1-1, mtr1-2 and prp20-1 carry alleles of a gene encoding a homolog of mammalian RCC1. In order to identify a protein interacting with RCC1, a series
of suppressors of the srm1-1 mutation were isolated as cold-sensitive mutants and one of the mutants, designated ded1-21, was found to be defective in the DED1 gene. The double mutant, srm1-1 ded1-21, could grow at 35° C, but not at 37° C. A revertant of srm1-1 ded1-21 that became able to grow at 37° C acquired another mutation in the SRM1 gene, indicating the tight relationship between SRM1 and DED1. In all the rcc1
- strains examined, the amount of mutated SRM1 proteins was reduced or not detectable at the nonpermissive temperature. While
mutated SRM1 protein was stabilized in all of the rcc1
- strains by the ded1-21 mutation, the ded1-21 mutation suppressed both srm1-1 and mtr1-2, but not the prp20-1 mutation, contrary to the previous finding that overproduction of the S. cerevisiae Ran homolog GSP1 suppresses prp20-1, but not srm1-1 or mtr1-2.
Received: 20 March 1996/Accepted: 1 July 1996 相似文献
9.
Arjun Singh Thomas L. Mason Robert A. Zimmermann 《Molecular & general genetics : MGG》1978,161(2):143-151
Summary A cytoplasmic mutant of Saccharomyces cerevisiae (E23-1) has been isolated that is resistant to erythromycin and cold sensitive for growth on nonfermentable carbon sources at 18°. Genetic analysis has shown that both of these properties probably result from a single mutation at the rib2 locus which maps close to or within the gene for the 21S rRNA of the mitochondrial 50S ribosomal subunit. Electrophoresis of total RNA extracted from purified mitochondria demonstrated that the 21S and 14S rRNA species from both mutant and wild-type cells were present in roughly equimolar quantities regardless of growth temperature. The mutant is therefore not defective in the synthesis of the 21S rRNA. Sucrose gradient analysis of the mitochondrial ribosomes in Mg2+-containing buffers revealed that approximate values for the ratio of 50S to 37S subunits were 1:1 for wild-type cells grown at either 18° or 32°, 0.5:1 for the mutant grown at 32° and 0.2:1 for the mutant grown at 18°. The subunit ratios were approximately 1:1 when Ca2+-containing buffers were used, however, In alls cases, 50S particles from the mutant grown at 18° lacked or contained markedly reduced amounts of two distinctive protein components that were present in the mutant at 32° and in the wild-type at both temperatures. In addition, no intact 21S RNA could be recovered from the mitochondrial ribosomes of the mutant grown at the restrictive temperature, even in the presence of Ca2+. These findings indicate that mitochondrial 50S ribosomal subunits produced by the mutant at 18° are structurally defective and raise the possibility that the defect results from an alteration in the gene for 21S rRNA.A preliminary report of this work was presented at the meeting on The Molecular Biology of Yeast, Cold Spring Harbor Laboratory, August 18–22, 1977 相似文献
10.
The period length of the circadian conidiation rhythm was examined in a mutant strain of Neurospora crassa, un-18, that is temperature sensitive for mycelial growth. The un-18 mutant showed a temperature-sensitive phenotype with respect to both mycelial growth and the period length of the conidiation
rhythm. Below 22° C, the un-18 mutation did not affect the period length, but at temperatures between 22° C and 32° C, the period length of the un-18 mutant was ∼2 h longer than that of the wild-type strain. The un-18
+ gene was cloned and was found to encode the second-largest subunit of RNA polymerase I, which is involved in the synthesis
of rRNA. These results indicate that a defect in ribosome synthesis, which must result in a lower rate of protein synthesis,
lengthens the period of the circadian conidiation rhythm in Neurospora.
Received: 17 October 1997 / Accepted: 26 April 1998 相似文献
11.
TSD2, a gene necessary for DNA synthesis in Ustilago maydis, was cloned by complementation of the temperature sensitive growth defect of a mutant known previously as pol1-1 and renamed here tsd2-1. Linkage analysis established that the cloned fragment contained an allele of tsd2-1 and not a suppressor. DNA sequence determination of the cloned DNA fragment indicated the presence of a single large uninterrupted
open reading frame capable of encoding a protein of 845 amino acids without homology to any known gene involved in DNA synthesis.
TSD2 was found to be cell cycle-regulated and mRNA levels peaked in early S or G1 phase.
Received: 27 March 1996 / Accepted: 28 August 1996 相似文献
12.
13.
Walters C Clarke A Cliff MJ Lund PA Harding SE 《European biophysics journal : EBJ》2000,29(6):420-428
A combination of sedimentation equilibrium and sedimentation velocity in the analytical ultracentrifuge is used to investigate
the hydrodynamic integrity and increased self-association interactions of the mutant GroEL Y203W when compared to the wild-type
GroEL molecule, which may be derived from increased hydrophobic exposure caused by the mutation. Sedimentation velocity has
revealed that three distinct species were present throughout the concentration ranges used, corresponding to 14-mer (GroEL
“super monomer”) and 28-mer (“super dimer”) subunit compositions with a small amount of 42-mer (“super trimer”), which, from
the relative concentration of each species, would give an estimated weight average molecular weight of (1.0 ± 0.1) × 106 Da. Sedimentation equilibrium gave an apparent weight average molecular weight (M
w,app) of (910,000 ± 5000) Da, which is in agreement with these findings. These results are in contrast to wild-type GroEL which,
in excellent agreement with the previous findings of Behlke and co-workers, revealed a single species with an M
w,app of (805,000 ± 5200) Da and a sedimentation coefficient s
0
20,w of (21.6 ± 0.3) S. We therefore conclude that the tryptophan mutation at the Y203 location causes a significant degree of
self-association of the GroEL 14-mer assembly (with dimer and trimer present). These findings would appear to correlate well
with the findings of Gibbons et al., who showed an increase in hydrophobic exposure due to this mutation.
Received: 4 January 2000 / Revised version: 5 April 2000 / Accepted: 5 April 2000 相似文献
14.
Using an antisense control strategy, we isolated an Aspergillus oryzae mutant that produced low levels of carboxypeptidases (CPases). The mutant TFC-1 expressed the antisense RNA of the structural gene of CPase O and showed about 30% of the CPase activity in the parent strain.
Gel filtration analysis indicated that this mutant decreased the CPase activities not only of CPase O but also of CPase O-1
and O-2. This result indicated that the antisense RNA was able to control the expression of the CPase genes as a group. Using
the mutant as a heterologous protein expression host that produced the low levels of CPases, a stable and higher level of
lysozyme expression could be obtained compared with the wild-type. In vitro proteolytic degradation assay also demonstrated that human lysozyme was degraded by purified CPase O.
Received: 16 June 1997 / Received last revision: 29 August 1997 / Accepted: 15 September 1997 相似文献
15.
In the absence of wounding, the epidermis is only rarely involved in cell or organ fusion events; in fact, intact epidermal
layers prevent graft unions. In Zea mays L. the mutation adherent1 (ad1) shows abnormal fusions between cells and organs. Fusions involve epidermal cells of vegetative and floral organs and occur
early in the ontogeny of organs. Even so, epidermal cell types differentiate normally in the fused regions and internal tissue
identities are maintained. In contrast, the extracellular matrix (cell wall and cuticle) of the epidermal cells is perturbed.
Epidermal cell walls in adherent leaves are thicker than normal. Epicuticular wax particles appear reduced in size and number
and altered in shape in mutant leaves. In addition, the outer epidermal cell walls of adherent leaves fluoresce when stained
with aniline blue, a reagent that binds to callose. Immunolocalizations to specific cell wall epitopes suggest that pectins
but not arabinogalactans may have a role in the fusion events. Taken together, these results suggest that the ad1 mutation results in cell-wall and epicuticular-wax defects similar to responses seen in wounding, pollination by incompatible
pollen, or pathogen attack. Since cell wall components and epicuticular waxes are extracellular secreted products, the ad1 mutation may disrupt normal functioning and/or composition of the secretory pathway and its cargo.
Received: 30 January 1998 / Accepted: 5 March 1998 相似文献
16.
K. Sugaya M. Ajimura H. Tsuji M. Morimyo K. Mita 《Molecular & general genetics : MGG》1998,258(3):279-287
A mutation in the RNA polymerase II largest subunit (RpII LS) that is related to abnormal induction of sister chromatid exchange
has previously been described the CHO-K1 cell mutant tsTM4. To elucidate the molecular basis of this effect we introduced
the mutation into the homologous site in the Schizosaccharomyces pombe rpb1 gene, which encodes RpII LS. Since the tsTM4 mutant exhibited a decrease in the rate of DNA synthesis in cells arrested in
S phase at the nonpermissive temperature, we focussed on the study of growth, the cell cycle, and chromosome stability at
various temperatures. First, we examined the effects of the mutation on haploid yeast cells. The mutant showed slower growth
than the wild type, but cell growth was not arrested at the nonpermissive temperature. When growing cells were shifted to
the nonpermissive temperature, an accumulation of cells in G1 and/or G0 was observed. Tetrad analysis suggested that these
phenotypes were associated with the mutation. In diploid cells, chromosome instability was detected by loss of intragenic
complementation between two alleles of the ade6 gene. An abnormal fraction of cells containing an intermediate DNA content was also observed by FACS analysis. The accumulation
of this fraction may reflect the fact that a large number of cells are in S phase or have an abnormal DNA content as a result
of chromosome instability. These observations demonstrate that the S. pomberpb1 mutant exhibits a phenotype very similar to that of the CHO-K1 cell mutant tsTM4.
Received: 1 October 1997 / Accepted: 29 December 1997 相似文献
17.
We describe the cDNA sequence for ARG7, the gene that encodes argininosuccinate lyase – a selectable nuclear marker – in Chlamydomonas reinhardtii. The 5′ end of the cDNA contains one more exon and the organisation of the mRNA is different from that predicted from the
genomic sequence. When expressed under the control of the endogenous RbcS2 promoter, the 2.22-kb cDNA complements the arg7 mutation as well as the genomic DNA. A linear cDNA fragment lacking promoter sequences is also able to complement, suggesting
that it could be used in promoter-trapping experiments. Despite the presence of a sequence encoding a potential chloroplast
transit peptide in the cDNA the protein is not targeted to the chloroplast, nor can it complement the arg7 mutation when expressed there. By inserting a T7 bacteriophage promoter into the plasmid, a version of the cDNA which is
able to complement both the C. reinhardtii arg7 mutant and the Escherichia coli argH mutant has been created. This modified Arg7 cDNA provides two advantages over the genomic DNA currently in use for gene tagging: it is shorter (6.2 kb versus 11.9 kb
for pARG7.8φ3), and the selectable marker used in C. reinhardtii is the same as that used in E. coli, making plasmid rescue of the tag much more likely to succeed.
Received: 2 June 1998 / Accepted: 25 September 1998 相似文献
18.
We have isolated a Saccharomyces cerevisiae mutant that shows an increased tendency to form cytoplasmic petites (respiration-deficient ρ− or ρ0 mutants) in response to treatment of cells growing on a solid medium with the DNA-damaging agent methyl methanesulfonate
or ultraviolet light. The mutation in this strain, atm1-1, was found to cause a single amino acid substitution in ATM1, a nuclear gene that encodes the mitochondrial ATP-binding cassette (ABC) transporter. When the mutant cells were grown in
liquid glucose medium, they accumulated free iron within the mitochondria and at the same time gave rise to spontaneous cytoplasmic
petite mutants, as seen previously in cells carrying a mutation in a gene homologous to the human gene responsible for Friedreich's
ataxia. Analysis of the effects of free iron and malonic acid (an inhibitor of oxidative respiration in mitochondria) on the
incidence of petites among the mutant cells indicated that spontaneous induction of petites was a consequence of oxidative
stress rather than a direct effect of either a defect in the ATM1 gene or the accumulation of free iron. We observed an increase in the incidence of strand breaks in the mitochondrial DNA
of the atm1-1 mutant cells. Furthermore, we found that rates of induction of petites and accumulation of strand breaks in mitochondrial
DNA were enhanced in the atm1-1 mutant by the introduction of another mutation, mhr1-1, which results in a deficiency in mitochondrial DNA repair. These observations indicate that spontaneous induction of petites
in the atm1-1 mutant is a consequence of oxidative damage to mitochondrial DNA mediated by enhanced accumulation of mitochondrial iron.
Received: 26 March 1999 / Accepted: 29 June 1999 相似文献
19.
B. Pérez-Vich J. Fernández R. Garcés J. M. Fernández-Martínez 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1999,98(3-4):496-501
Sunflower genotypes with increased levels of palmitic acid (C16 : 0) in the seed oil could be useful for food and industrial
applications. The objective of the present study was to determine the inheritance of the high C16 : 0 content in the sunflower
mutant line CAS-5 (>25% of the total oil fatty acids). This mutant was reciprocally crossed with the lines HA-89 (5.7% C16 : 0)
and BSD-2-691 (5.4% C16 : 0), the latter being the parental line from which CAS-5 was isolated. No maternal effect for the
C16 : 0 content was observed from the analysis of F1 seeds in any of the crosses. The inheritance study of the C16 : 0 content in F1, F2 and BC1F1 seeds from the crosses of CAS-5 with its parental line BSD-2-691 indicated that the segregation fitted a model of two alleles
at one locus with partial dominance for the low content. The analysis of the fatty acid composition in the F2 populations from the crosses with HA-89 revealed a segregation fitting a ratio 19 : 38 : 7 for low (<7.5%), middle (7.5–15%),
and high (>25%) C16 : 0 content, respectively. This segregation was explained on the basis of three loci (P1, P2, P3) each having two alleles showing partial dominance for low content. The genotypes with a high C16 : 0 content were homozygous
for the recessive allele p1 and for at least one of the other two recessive alleles, p2 or p3. This model was further confirmed with the analysis of the F3 and the BC1F1 generations. It was concluded that both the recessive alleles p2 and p3 were already present in the BSD-2-691 line, the allele p1 being the result of a mutation from P1. This genetic study will facilitate breeding strategies associated with the incorporation of the high C16 : 0 trait into
agronomically acceptable sunflower hybrids.
Received: 30 March 1998 / Accepted: 13 August 1998 相似文献
20.
Summary. Protein L4 from the thermophilic bacterium Thermus thermophilus (TthL4) was heterologously overproduced in Escherichia coli cells and purified under native conditions by using ion exchange chromatography. Although it’s known strong binding to RNA
(23S rRNA as well as mRNA) the yield of the purified protein was 6 mg per 10 g of cells and it is similar to that referred
for Thermotoga maritima L4 ribosomal protein.
In addition, E. coli cells harboring the wild type Thermus thermophilus L4 (wtTthL4) ribosomal protein as well as its mutant having changed the highly conserved glutamic acid 56 by alanine (TthL4-Ala
56) were incorporated into E. coli ribosomes after transformation of the host cells with the recombined vector. The cells having incorporated the mutant TthL4-Ala56
are more sensitive against erythromycin related to that containing the wtTthL4 protein.
The resistance to the drug indicates that the mutated amino acid Glu56 is probably critical for the local ribosomal conformation
and that its mutation induces conformational disturbances that are “transferred” to the entrance of the major exit tunnel,
the place where the drug does bind. 相似文献