BIO - TERMS - PEPTIDE

Question 1

affinity hypothesis

Answer 1

Hypothesis that proposes how the choice between negative selection and positive selection of T cells in the thymus is made, according to the strength of self-peptide:MHC binding by the T-cell receptor. Low-affinity interactions rescue the cell from death by neglect, leading to positive selection; high-affinity interactions induce apoptosis and thus negative selection.

Question 2

amyloid-b peptides

Answer 2

Plaques and neurofibrillary tangles in brain tissue found in Alzheimer’s disease. amyloid precursor protein Precursor to amyloid-b peptides found in brain tissue of Alzheimer’s disease. amylopectin Starch consisting of straight chains of glucose with branching.

Question 3

antimicrobial peptide (AMP)

Answer 3

An antibiotic that is bactericidal and has a broad spectrum of activity; see bacteriocin.

Question 4

antimicrobial peptides, antimicrobial proteins

Answer 4

Amphipathic peptides or proteins secreted by epithelial cells and phagocytes that kill a variety of microbes nonspecifically, mainly by disrupting cell membranes. Antimicrobial peptides in humans include the defensins, the cathelicidins, the histatins, and RegIIIγ.

Question 5

bradykinin

Answer 5

A vasoactive peptide that is produced as a result of tissue damage and acts as an inflammatory mediator.

Question 6

C-peptide

Answer 6

A biologically inactive fragment of proinsulin that is released together with insulin.

Question 7

C1 inhibitor (C1INH)

Answer 7

An inhibitor protein for C1 that binds and inactivates C1r:C1s enzymatic activity. Deficiency in C1INH causes hereditary angioedema through production of vasoactive peptides that cause subcutaneous and laryngeal swelling.

Question 8

calprotectin

Answer 8

A complex of heterodimers of the antimicrobial peptides S100A8 and S100A9, which sequester zinc and manganese from microbes. Produced in abundance by neutrophils, and in lesser amounts by macrophages and epithelial cells.

Question 9

cathelicidins

Answer 9

Family of antimicrobial peptides that in humans has one member.

Question 10

cell wall

Answer 10

The outer covering of most bacterial, fungal, algal, and plant cells; in bacteria, it consists of peptidoglycan.

Question 11

class I MHC protein

Answer 11

One of two classes of major histocompatibility complex (MHC) protein. Found on the surface of almost all vertebrate cell types, where it can present foreign peptides derived from a pathogen such as a virus to cytotoxic T cells.

Question 12

class II-associated invariant chain peptide (CLIP)

Answer 12

A peptide of variable length cleaved from the invariant chain (Ii) by proteases. It remains associated with the MHC class II molecule in an unstable form until it is removed by the HLA-DM protein.

Question 13

Competence (Com) proteins

Answer 13

Proteins that mediate the process of transformation in bacteria. Their synthesis is induced by small peptides called competence pheromones.

Question 14

cryptdins

Answer 14

α-Defensins (antimicrobial peptides) made by the Paneth cells of the small intestine.

Question 15

default pathway

Answer 15

The transport pathway of proteins directly to the cell surface via the nonselective constitutive secretory pathway, entry into which does not require a particular signal. defensin Positively charged, amphipathic, antimicrobial peptide—secreted by epithelial cells—that binds to and disrupts the membranes of many pathogens.

Question 16

Edman degradation

Answer 16

A method for N-terminal sequencing of peptide chains by treatment with N-phenylisothiocyanate.

Question 17

ER signal sequence

Answer 17

N-terminal signal sequence that directs proteins to enter the endoplasmic reticulum (ER). Cleaved off by signal peptidase after entry.

Question 18

ERp57

Answer 18

A chaperone protein involved in loading peptide onto MHC class I molecules in the endoplasmic reticulum.

Question 19

fMet-Leu-Phe (fMLF) receptor

Answer 19

A pattern recognition receptor for the peptide fMet-Leu-Phe, which is specific to bacteria, on neutrophils and macrophages. fMet-Leu-Phe acts as a chemoattractant.

Question 20

Grass

Answer 20

A serine protease of Drosophila that functions downstream of peptidoglycan-recognition proteins (PGRPs) and Gram-negative binding proteins (GNBPs) to initiate the proteolytic cascade leading to Toll activation.

Question 21

H2-M3

Answer 21

A nonclassical MHC class Ib protein in mice that can bind and present peptides having an N-formylated amino terminus for recognition by CD8 T cells.

Question 22

histatins

Answer 22

Antimicrobial peptides constitutively produced by the parotid, sublingual, and submandibular glands in the oral cavity. Active against pathogenic fungi such as Cryptococcus neoformans and Candida albicans.

Question 23

HLA-DM

Answer 23

An invariant MHC protein resembling MHC class II in humans that is involved in loading peptides onto MHC class II molecules. A homologous protein in mice is called H-2M, or sometimes H2-DM.

Question 24

Imd (immunodeficiency) signaling pathway

Answer 24

A defense against Gramnegative bacteria in insects that results in the production of antimicrobial peptides such as diptericin, attacin, and cecropin.

Question 25

interaction domain

Answer 25

Compact protein module, found in many intracellular signaling proteins, that binds to a particular structural motif (e.g., a short peptide sequence, a covalent modification, or another protein domain) in another protein or lipid.

Question 26

kinin system

Answer 26

An enzymatic cascade of plasma proteins that is triggered by tissue damage to produce several inflammatory mediators, including the vasoactive peptide bradykinin.

Question 27

lipocalin-2

Answer 27

An antimicrobial peptide produced in abundance by neutrophils and mucosal epithelial cells that inhibits bacterial and fungal growth by limiting availability of iron.

Question 28

Matrix assisted laser desorption/ionization (MALDI)

Answer 28

Ion source technique in mass spectrometers for ionization of biomacromolecules (e.g., peptides and proteins) present in a solid phase.

Question 29

Metallothiolome

Answer 29

Entirety of thiol peptides and their metal complexes in an organism or its parts (cells, body fluids, or tissues).

Question 30

Metallothiolomics

Answer 30

A systematic investigation of the thiol peptide regulated metal homeostasis.

Question 31

muramyl dipeptide (MDP)

Answer 31

A component of the peptidoglycan of most bacteria that is recognized by the intracellular sensor NOD2.

Question 32

neutrophil elastase

Answer 32

Proteolytic enzyme stored in the granules of neutrophils that is involved in the processing of antimicrobial peptides.

Question 33

PA28 proteasome-activator complex

Answer 33

A multisubunit protein complex induced by interferon-γ that takes the place of the 19S regulatory cap of the proteasome and increases the rate of peptides exiting from the proteasome catalytic core.

Question 34

Paneth cells

Answer 34

Specialized epithelial cells at the base of the crypts in the small intestine that secrete antimicrobial peptides.

Question 35

peptide-loading complex (PLC)

Answer 35

A protein complex in the endoplasmic reticulum that loads peptides onto MHC class I molecules.

Question 36

peptidergic

Answer 36

Describing neurons or synapses that produce and release peptide neurotransmitters.

Question 37

peptidoglycan-recognition proteins (PGRPs)

Answer 37

A family of Drosophila proteins that bind peptidoglycans from bacterial cell walls that serve to initiate the proteolytic cascade of the TOLL pathway.

Question 38

phalloidin

Answer 38

A peptide toxin produced by Amanita phalloides, affects plasma membrane function.

Question 39

primary granules

Answer 39

Granules in neutrophils that correspond to lysosomes and contain antimicrobial peptides such as defensins and other antimicrobial agents.

Question 40

Qa-1 determinant modifiers (Qdm)

Answer 40

A class of peptides derived from the leader peptides of various HLA class I molecules that can be bound by the human HLA-E and murine Qa-1 proteins, and then are recognized by the inhibitory NKG2A:CD94 receptor.

Question 41

secondary granules

Answer 41

Type of granule in neutrophils that stores certain antimicrobial peptides.

Question 42

secretory granule

Answer 42

A spherical membrane-enclosed vesicle about 100 nm in diameter containing peptides intended for secretion by exocytosis; also called dense-core vesicle.

Question 43

α-defensins

Answer 43

A class of antimicrobial peptides produced by neutrophils and the Paneth cells of the intestine.

Question 44

β-defensins

Answer 44

Antimicrobial peptides made by virtually all multicellular organisms. In mammals they are produced by the epithelia of the respiratory and urogenital tracts, skin, and tongue.

Question 45

β5t

Answer 45

Alternative proteasome subunit expressed by thymic epithelial cells that substitutes for β5 to produce the thymoproteasome involved in generating peptides encountered by thymocytes during development.

Question 46

γ-glutamyl diaminopimelic acid (iE-DAP)

Answer 46

A product of degradation of the peptidoglycan of Gram-negative bacteria. It is sensed by NOD1.