Molecular transport in Neurospora crassa I. Biochemical properties of a phenylalanine permease

DeBusk, Betty G.; DeBusk, A. G.

doi:10.1016/0304-4165(65)90229-1

Cited by 54 publications

(17 citation statements)

References 6 publications

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“…In the filamentous fungus Neurospora crassa, transport is accomplished by three constitutive amino acid permeases and three specialized permeases. The constitutive permeases include a neutral amino acid-specific (N) system, a basic amino acid-specific (B) system, and a general (G) system that can transport all classes of amino acid (5,7,18,20,22,23,37). Three additional systems that function during advanced stages of development have been proposed for the transport of the imino acid proline, of acidic amino acids, and of the sulfurcontaining amino acid methionine during sulfur limitation (10,24,25,38,40).…”

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confidence: 99%

Participation of an extracellular deaminase in amino acid utilization by Neurospora crassa

DeBusk¹,

Ogilvie²

1984

J Bacteriol

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A strain of Neurospora crassa defective in amino acid transport can utilize a variety of amino acids for growth when readily metabolizable nitrogen is limiting. Growth is accompanied by the production of an extracellular deaminase that converts the amino acid to its respective keto acid plus equimolar quantities of utilizable nitrogen in the ammonium ion form. Production of the deaminase is subject to ammonium repression. The relationship between the ability of an amino acid to trigger deaminase production and the presence of particular amino acid permease deficiencies is complex. Four classes of amino acids have been defined with respect to this relationship. The existence of multiple extracellular deaminases is discussed.

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confidence: 99%

Participation of an extracellular deaminase in amino acid utilization by Neurospora crassa

DeBusk¹,

Ogilvie²

1984

J Bacteriol

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“…RNase A inhibition of transport activity apparently does not occur by allowing efflux of previously transported amino acid. It has been reported that addition of dinitrophenol or sodium azide to transporting cells will rapidly release previously transported L-phenylalanine (4). In this study conidia that contain previously transported amino acid do not lose any L-phenylalanine isotopic activity during a 7-min period after addition of RNase A.…”

Section: Discussionmentioning

confidence: 66%

“…These include a system specific for neutral and aromatic amino acids (4,7,8,10,17,18,25,26), a system specific for basic amino acids (1,11,13,21,26,27), and a system in which both types of amino acids compete for entry (12,26). These permeases are active in ungerminated conidia (4,13,26) during the onset of conidial germination (22) and in mycelia (7,(10)(11)(12)25). Genetic loci that control the function of these three particular transport systems segregate independently from one another (26; Edith Wong and A. Gib DeBusk, personal communication).…”

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confidence: 99%

Effects of ribonuclease A on amino acid transport in Neurospora crassa

Stuart¹,

Woodward²

1975

J Bacteriol

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Incubation of Neurospora crassa conidia with ribonuclease (RNase) A reduces transport of L-phenylalanine by those cells. Under similar conditions, oxidized RNase A, RNase T,, and RNase T2 do not have this effect. Incubation of conidia with active RNase covalently attached to polyacrylamide beads reduces L-phenylalanine transport. This indicates that the site of enzymatic action is at the cell surface. At the lower concentration of enzyme used in this study, incubation with RNase A reduces transport of L-phenylalanine by the general (G) amino acid permease. Increasing the enzyme concentration results in reduction of transport by the neutral aromatic (N)-specific permease. The increased transport activity that accompanies onset of conidial germination is also sensitive to incubation with RNase A. Application of the enzyme to actively transporting cells does not release amino acid transported prior to enzyme addition. Cells cultured on media supplemented with [2-"C]uridine release isotopic activity after RNase A incubation. Analogous treatments with Pronase, RNase T,, RNase T2, or deoxyribonuclease I do not release isotope activity.Pronase treatment does reduce L-phenylalanine transport. Incubation of conidia with RNase A also inhibits germination of those conidia. tion was 0.514 M; and (ii) Vogel salts (23) diluted 100-fold at pH 6.0.Conidia were collected on glass-fiber filters (Whatman GF/C, 2.4 cm) and digested with tissue solubilizer (NCS, Amersham/Searle), and the radioactivity was determined in a Beckman LS-100 scintillation counter with toluene-Omnifluor (New England Nu-41 on August 1, 2020 by guest

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“…Since glutamine transport occurs by means of the N and G systems and transport by each of these systems is known to be an active process, we expected glutamine transport also to be dependent upon metabolic energy (DeBusk & DeBusk, 1965. This expectation was confirmed by examining glutamine transport by the wild-type strain in the presence of the metabolic inhibitor 2,4-dinitrophenol (Fig.…”

Section: Physiological Properties Of L-glutamine Transportmentioning

confidence: 70%

Transport of L-Glutamine by Neurospora

DeBusk¹,

Ogilvie²

1985

Microbiology

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The transport of the neutral amino acid L-glutamine by Neurospora crassa occurred by means of two permeases : the neutral-specific permease and the general permease. For both transport systems, accumulation of L-glutamine was a saturable process that occurred against a concentration gradient and was dependent upon metabolic energy, suggesting that accumulation is a carrier-mediated active transport process. The transported glutamine was incorporated into cellular protein. The kinetic values K , and V,,, were determined for glutamine transport by both systems. The glutamine analogues methionine sulphoximine and yglutamyl hydroxamate appear to be transported by the same permeases that transport glu tamine.In addition to determining the physiological properties of glutamine transport, we examined whether thepmn;pmb;pmg;nit-2 strain could transport this amino acid. This strain is defective for constitutive amino acid transport and for the ability to utilize amino acids as sole nitrogen sources, with the exception of glutamine. No glutamine transport was detected, suggesting that glutamine utilization by this strain is not due to its ability to transport this amino acid.

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Molecular transport in Neurospora crassa I. Biochemical properties of a phenylalanine permease

Cited by 54 publications

References 6 publications

Participation of an extracellular deaminase in amino acid utilization by Neurospora crassa

Participation of an extracellular deaminase in amino acid utilization by Neurospora crassa

Effects of ribonuclease A on amino acid transport in Neurospora crassa

Transport of L-Glutamine by Neurospora

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